Meningococcal disease is rare but serious, often striking previously healthy adolescents or young adults, with substantial morbidity and mortality. The incidence of meningococcal disease in the USA declined even prior to the issuance of routine recommendations for vaccination, although an uptick in incidence has occurred since 2022. Routine recommendations for adolescent MenACWY vaccination were issued in 2005, and recommendations for adolescent MenB vaccination based on shared clinical decision-making (SCDM) were issued in 2015. Although meningococcal vaccines are safe and effective, their limited duration of protection coupled with low disease incidence result in a high cost per case averted by vaccination, most notably with MenB vaccines. The low cost-effectiveness raises ethical concerns about resource use and the role of economic analyses in policy decisions. However, the potential for substantial public health impact remains. Outer membrane vesicle (OMV)-containing MenB vaccines provide some protection against gonorrhea infections. The recent development of pentavalent ABCWY vaccines provide the opportunity to reduce the number of injections and simplify implementation, provided MenACWY and MenB vaccine schedules are harmonized. Vaccine attributes, implementation issues, and resource utilization will be important considerations in optimization of the US adolescent meningococcal vaccination strategy.

Neisseria meningitidis is a common commensal bacterium of the nasopharynx that can cause invasive meningococcal disease (IMD). In comparison, N. gonorrhoeae is always a pathogen usually limited to mucosal sites. However, increased evidence for overlapping clinical syndromes is emerging. We compared N. meningitidis samples from a urogenital outbreak in Australia with sequences from the United States and other countries. We conducted phylogenetic analyses to assess relatedness and examine for genomic changes associated with meningococcal adaptation; we collated a total of 255 serogroup Y (MenY), sequence type (ST) 1466 isolate assemblies. Most urogenital isolates originated from Australia; those isolates formed a distinct clade, most closely related genomically to recent US IMD isolates. No specific genomic changes suggested niche adaptation or associated clinical manifestations. The MenY ST1466 N. meningitidis isolates circulating in Australia and the United States are capable of causing both urethritis and invasive meningococcal disease.

Two meningococcal serogroup B vaccines are licensed for use in the United States. In August 2024, the Food and Drug Administration (FDA) changed the label for the meningococcal serogroup B MenB-4C vaccine (Bexsero) from a 2-dose schedule (intervals of 0 and ≥1 month) to a 2-dose schedule (0 and 6 months) and added a 3-dose schedule (0, 1-2, and 6 months), based on new immunogenicity data. On October 24, 2024, the Advisory Committee on Immunization Practices (ACIP) voted to update its recommendations for the MenB-4C dosing interval and schedule to align with the new FDA label. ACIP recommends extending the interval for the 2-dose series of MenB-4C from 0 and ≥1 month to 0 and 6 months for healthy adolescents and young adults aged 16-23 years based on shared clinical decision-making and has added a recommendation for a 3-dose series with doses administered at 0, 1-2, and 6 months for persons aged ≥10 years at increased risk. The updated ACIP recommendations for MenB-4C align with existing ACIP recommendations for the other FDA-licensed meningococcal serogroup B vaccine, MenB-FHbp (Trumenba).

Invasive Haemophilus influenzae type b (Hib) disease is a serious bacterial infection that disproportionally affects American Indian and Alaska Native (AI/AN) populations. Hib vaccination with a monovalent Hib conjugate vaccine consisting of Hib capsular polysaccharide (polyribosylribitol phosphate [PRP]) conjugated to outer membrane protein complex of Neisseria meningitidis serogroup B, PRP-OMP (PedvaxHIB, Merck and Co., Inc.) has historically been preferred for AI/AN infants, who are at increased risk for invasive Hib disease, because it provides substantial protection after the first dose. On June 26, 2024, CDC's Advisory Committee on Immunization Practices (ACIP) recommended that a hexavalent, combined diphtheria and tetanus toxoids and acellular pertussis (DTaP), inactivated poliovirus (IPV), Hib conjugate, and hepatitis B (HepB) vaccine, DTaP-IPV-Hib-HepB (Vaxelis, MSP Vaccine Company) should be included with monovalent PRP-OMP in the preferential recommendation for AI/AN infants because of the PRP-OMP Hib component. A primary Hib vaccination series consisting of either 1) monovalent PRP-OMP (2-dose series at ages 2 and 4 months) or 2) DTaP-IPV-Hib-HepB (3-dose series at ages 2, 4, and 6 months) is preferred for AI/AN infants. DTaP-IPV-Hib-HepB is only indicated for use in infants at ages 2, 4, and 6 months and should not be used for the booster doses of Hib, DTaP, or IPV vaccines. For the booster dose of Hib vaccine, no vaccine formulation is preferred for AI/AN children; any Hib vaccine (except DTaP-IPV-Hib-HepB) should be used. This report summarizes evidence considered for these recommendations and provides clinical guidance for the use of Hib-containing vaccines among AI/AN infants and children.

Invasive meningococcal disease (IMD), caused by infection with the bacterium Neisseria meningitidis, usually manifests as meningitis or septicemia and can be severe and life-threatening (1). Six serogroups (A, B, C, W, X, and Y) account for most cases (2). N. meningitidis is transmitted person-to-person via respiratory droplets and oropharyngeal secretions. Asymptomatic persons can carry N. meningitidis and transmit the bacteria to others, potentially causing illness among susceptible persons. Outbreaks can occur in conjunction with large gatherings (3,4). Vaccines are available to prevent meningococcal disease. Antibiotic prophylaxis for close contacts of infected persons is critical to preventing secondary cases (2).

BACKGROUND: An increased pertussis burden has been demonstrated among Hispanic or Latino and American Indian or Alaska Native (AI/AN) infants. However, data on potential disparities among other age and racial groups are limited. METHODS: We analyzed pertussis cases reported through Enhanced Pertussis Surveillance from 2010 to 2017. Pertussis and severe pertussis incidence were calculated by race (White, Black or African American, AI/AN, and Asian or Pacific Islanders), ethnicity (Hispanic or Latino and non-Hispanic or non-Latino), and age. RESULTS: Compared with White persons, overall incidence was lower among Black or African American (incidence rate ratio [IRR], .57; 95% confidence interval [CI], .53-.61), AI/AN (IRR, 0.65; 95% CI, .58-.72), and Asian or Pacific Islander persons (IRR, 0.39; 95% CI, .35-.43). Overall incidence of pertussis was higher (1.5-fold; 95% CI, 1.37-1.60) among Hispanic or Latino compared with non-Hispanic or non-Latino adults, potentially related to household size or lower pertussis vaccine uptake among adult Hispanic or Latino cases. Severe pertussis incidence was similar among Black or African American and AI/AN persons compared with White persons. Among infants, severe pertussis incidence was 1.4-fold higher (95% CI, 1.03-1.82) among Black or African American infants than among White infants, and 2.1-fold higher (95% CI, 1.67-2.57) among Hispanic or Latino infants than non-Hispanic or non-Latino infants. CONCLUSIONS: The contrast between lower reported incidence but similar or higher severe pertussis incidence among Black or African American and AI/AN persons compared with White persons warrants further investigation and may reflect underdiagnosis or underreporting of mild disease.

Meningococcal disease is a life-threatening invasive infection caused by Neisseria meningitidis. Two quadrivalent (serogroups A, C, W, and Y) meningococcal conjugate vaccines (MenACWY) (MenACWY-CRM [Menveo, GSK] and MenACWY-TT [MenQuadfi, Sanofi Pasteur]) and two serogroup B meningococcal vaccines (MenB) (MenB-4C [Bexsero, GSK] and MenB-FHbp [Trumenba, Pfizer Inc.]), are licensed and available in the United States and have been recommended by CDC's Advisory Committee on Immunization Practices (ACIP). On October 20, 2023, the Food and Drug Administration approved the use of a pentavalent meningococcal vaccine (MenACWY-TT/MenB-FHbp [Penbraya, Pfizer Inc.]) for prevention of invasive disease caused by N. meningitidis serogroups A, B, C, W, and Y among persons aged 10-25 years. On October 25, 2023, ACIP recommended that MenACWY-TT/MenB-FHbp may be used when both MenACWY and MenB are indicated at the same visit for the following groups: 1) healthy persons aged 16-23 years (routine schedule) when shared clinical decision-making favors administration of MenB vaccine, and 2) persons aged ≥10 years who are at increased risk for meningococcal disease (e.g., because of persistent complement deficiencies, complement inhibitor use, or functional or anatomic asplenia). Different manufacturers' serogroup B-containing vaccines are not interchangeable; therefore, when MenACWY-TT/MenB-FHbp is used, subsequent doses of MenB should be from the same manufacturer (Pfizer Inc.). This report summarizes evidence considered for these recommendations and provides clinical guidance for the use of MenACWY-TT/MenB-FHbp.

During January 28-May 5, 2019, a meningitis outbreak caused by Neisseria meningitidis serogroup C (NmC) occurred in Burkina Faso. Demographic and laboratory data for meningitis cases were collected through national case-based surveillance. Cerebrospinal fluid was collected and tested by culture and real-time PCR. Among 301 suspected cases reported in 6 districts, N. meningitidis was the primary pathogen detected; 103 cases were serogroup C and 13 were serogroup X. Whole-genome sequencing revealed that 18 cerebrospinal fluid specimens tested positive for NmC sequence type (ST) 10217 within clonal complex 10217, an ST responsible for large epidemics in Niger and Nigeria. Expansion of NmC ST10217 into Burkina Faso, continued NmC outbreaks in the meningitis belt of Africa since 2019, and ongoing circulation of N. meningitidis serogroup X in the region underscore the urgent need to use multivalent conjugate vaccines in regional mass vaccination campaigns to reduce further spread of those serogroups.

Meningococcal disease, caused by the bacterium Neisseria meningitidis, is a rare but life-threatening illness that requires prompt antibiotic treatment for patients and antibiotic prophylaxis for their close contacts. Historically, N. meningitidis isolates in the United States have been largely susceptible to the antibiotics recommended for prophylaxis, including ciprofloxacin. Since 2019, however, the number of meningococcal disease cases caused by ciprofloxacin-resistant strains has increased. Antibiotic prophylaxis with ciprofloxacin in areas with ciprofloxacin resistance might result in prophylaxis failure. Health departments should preferentially consider using antibiotics other than ciprofloxacin as prophylaxis for close contacts when both of the following criteria have been met in a local catchment area during a rolling 12-month period: 1) the reporting of two or more invasive meningococcal disease cases caused by ciprofloxacin-resistant strains, and 2) ≥20% of all reported invasive meningococcal disease cases are caused by ciprofloxacin-resistant strains. Other than ciprofloxacin, alternative recommended antibiotic options include rifampin, ceftriaxone, or azithromycin. Ongoing monitoring for antibiotic resistance of meningococcal isolates through surveillance and health care providers' reporting of prophylaxis failures will guide future updates to prophylaxis considerations and recommendations.

Persons with HIV (PWH) are at increased risk for bacterial infections, and previous publications document an increased risk for invasive meningococcal disease (IMD) in particular. This analysis provides evidence that PWH face a 6-fold increase in risk for IMD based on Active Bacterial Core surveillance data collected during 2009-2019.

Meningococcal meningitis, caused by the bacterium Neisseria meningitidis, is a devastating disease that can lead to death within 24 h of onset. The meningitis belt of Africa—a region south of the Sahara desert that spans 26 countries, from Senegal in the west to Ethiopia in the east—experiences the highest global burden of meningococcal meningitis and frequent epidemics.1 Historically, most epidemics in this region were caused by N. meningitidis serogroup A.1 However, beginning in 2010, a novel meningococcal serogroup A conjugate vaccine (MenACV; MenAfriVac) was introduced across the region.1 To date, mass MenACV vaccination campaigns targeting people aged 1–29 years have been implemented in 24 countries of the belt; 15 of these countries have also introduced the vaccine into their routine childhood immunization programmes.2 MenACV introduction in the belt has been an incredible public health success, with elimination of serogroup A epidemics and near-elimination of serogroup A disease.1 Much of the vaccine’s success can be attributed to its ability not only to prevent disease but also to eliminate asymptomatic meningococcal carriage.1 Since asymptomatic carriage is the primary source of meningococcal transmission, eliminating carriage is critical to provide population herd immunity.1 | | While MenACV introduction has eliminated serogroup A epidemics from the meningitis belt, serogroups C, W and X continue to cause disease and epidemics in the region.1 Serogroup C in particular has recently caused large outbreaks, including over 14 000 suspected meningitis cases in Nigeria in 2017 and recurrent outbreaks in Niger in 2020–2023.3,4 The ongoing devastation caused by these outbreaks highlights the urgent need for an affordable meningococcal conjugate vaccine for the meningitis belt that can protect against serogroups A, C, W and X.

BACKGROUND: College students are at increased risk for invasive meningococcal disease, but which students are most at risk is unclear. METHODS: US meningococcal disease cases in persons aged 18-24 years during 2014-2017 were included. Patients were classified as undergraduate students or other persons. Incidence in different student and non-student populations was compared. RESULTS: During 2014-2017, 229 meningococcal disease cases were reported in persons aged 18-24 years; 120 were in undergraduate students. Serogroup B accounted for 74% of cases in students. Serogroup B disease incidence was 4-fold higher in undergraduate students, 11.8-fold higher among first-year undergraduate students, and 8.6-fold higher among residence hall residents versus non-undergraduates. During outbreaks, students affiliated with Greek life had a 9.8-fold higher risk of disease compared to other students. A significantly higher party school ranking was observed for schools with sporadic or outbreak cases when compared to schools with no cases. CONCLUSIONS: The findings of increased disease risk among first-year students and those living on campus or affiliated with Greek life can inform shared clinical decision-making for serogroup B vaccines to prevent this rare but serious disease. These data also can inform school serogroup B vaccination policies and outbreak response measures.

Meningococcal disease is a serious but rare disease in the United States. Prior publications suggest incidence differs among privately vs publicly-insured persons, and that incidence is higher among persons experiencing homelessness (PEH) than persons not known to be experiencing homelessness (non-PEH). Using insurance claims data for persons aged <1 to 64 years, we calculated meningococcal disease incidence among a population with employer-sponsored commercial insurance and persons enrolled in state Medicaid programs nationwide. We also examined meningococcal disease incidence by PEH status in Medicaid data. From 2016 through 2019, persons who met our study inclusion criteria contributed a total of 84,460,548 person-years (PYs) to our analysis of commercial insurance data and 253,496,622 PYs to our analysis of Medicaid data. Incidence was higher among persons enrolled in Medicaid (0.12 cases per 100,000 PYs) than persons with commercial insurance (0.06 cases per 100,000 PYs). Incidence was 3.17 cases per 100,000 PYs among PEH in Medicaid, 27 times higher than among non-PEH in Medicaid. Understanding the underlying drivers of the higher meningococcal disease incidence among PEH and persons enrolled in Medicaid may inform prevention strategies for populations experiencing a higher burden of disease.

In May 2023, the Detroit Health Department was notified of four cases of invasive nontypeable Haemophilus influenzae (Hi) disease among students attending the same elementary school and grade, all with illness onsets within 7 days. Three patients were hospitalized, and one died. Most U.S. cases of invasive Hi disease are caused by nontypeable strains. No vaccines against nontypeable or non-type b Hi strains are currently available. Chemoprophylaxis is not typically recommended in response to nontypeable Hi cases; however, because of the high attack rate (four cases among 46 students; 8.7%), rifampin prophylaxis was recommended for household contacts of patients with confirmed cases and for all students and staff members in the school wing where confirmed cases occurred. Only 10.8% of students for whom chemoprophylaxis was recommended took it, highlighting gaps in understanding among caregivers and health care providers about persons for whom chemoprophylaxis was recommended. Public health authorities subsequently enhanced communication and education to the school community, improved coordination with health care partners, and established mass prophylaxis clinics at the school. This outbreak highlights the potential for nontypeable Hi to cause serious illness and outbreaks and the need for chemoprophylaxis guidance for nontypeable Hi disease. Achieving high chemoprophylaxis coverage requires education, communication, and coordination with community and health care partners.

Meningococcal disease, caused by the bacterium Neisseria meningitidis, is a sudden-onset, life-threatening illness that typically occurs as meningitis or meningococcemia. The most common signs and symptoms of meningitis include fever, headache, and stiff neck; the most common signs and symptoms of meningococcemia are fever, chills, fatigue, vomiting, diarrhea, cold hands and feet, and severe aches or pain.* Quadrivalent meningococcal conjugate vaccination (MenACWY) is routinely recommended for adolescents and persons at increased risk for meningococcal disease (1), including those with HIV. In 2016, a 2-dose series of MenACWY was recommended by the Advisory Committee on Immunization Practices (ACIP) for persons with HIV and incorporated into the U.S. immunization schedule. Coverage among persons with HIV, however, remains low: in a study of administrative claims data during January 2016–March 2018, only 16.3% of persons with HIV received ≥1 doses of MenACWY vaccine within 2 years after their diagnosis (2). This report describes an increase in meningococcal disease among persons with HIV in the United States in 2022. Data are typically finalized in the fall of the next year; therefore, this report is based on preliminary data for 2022.

BACKGROUND: Post-exposure prophylaxis (PEP) for pertussis is recommended for household contacts of pertussis cases in the United States within 21 days of exposure, but data on PEP effectiveness for prevention of secondary cases in the setting of widespread pertussis vaccination are limited. We implemented a multi-state evaluation of azithromycin PEP use and effectiveness among household contacts. METHODS: Culture- or PCR-confirmed pertussis cases were identified through surveillance. Household contacts were interviewed within 7 days of case report and again 14-21 days later. Interviewers collected information on exposure, demographics, vaccine history, prior pertussis diagnosis, underlying conditions, PEP receipt, pertussis symptoms, and pertussis testing. A subset of household contacts provided nasopharyngeal and blood specimens during interviews. RESULTS: Of 299 household contacts who completed both interviews, 12 (4%) reported not receiving PEP. There was no evidence of higher prevalence of cough or pertussis symptoms among contacts who did not receive PEP. Of 168 household contacts who provided at least one nasopharyngeal specimen, four (2.4%) were culture or PCR positive for B. pertussis; three of these received PEP prior to their positive test result. Of 156 contacts with serologic results, 14 (9%) had blood specimens that were positive for IgG anti-pertussis toxin (PT) antibodies; all had received PEP. CONCLUSIONS: Very high PEP uptake was observed among household contacts of pertussis patients. Although the number of contacts who did not receive PEP was small, there was no difference in prevalence of pertussis symptoms or positive laboratory results among these contacts compared with those who did receive PEP.

BACKGROUND: Descriptions of changes in invasive bacterial disease (IBD) epidemiology during the COVID-19 pandemic in the United States are limited. METHODS: We investigated changes in the incidence of IBD due to Streptococcus pneumoniae, Haemophilus influenzae, group A Streptococcus (GAS), and group B Streptococcus (GBS). We defined the COVID-19 pandemic period as March 1-December 31, 2020. We compared observed IBD incidences during the pandemic to expected incidences, consistent with January 2014-February 2020 trends. We conducted secondary analysis of a healthcare database to assess changes in testing by blood and cerebrospinal fluid (CSF) culture during the pandemic. RESULTS: Compared with expected incidences, the observed incidences of IBD due to S. pneumoniae, H. influenzae, GAS, and GBS were 58%, 60%, 28%, and 12% lower during the pandemic period of 2020, respectively. Declines from expected incidences corresponded closely with implementation of COVID-19-associated non-pharmaceutical-interventions (NPIs). Significant declines were observed across all age, race groups and surveillance sites for S pneumoniae and H influenzae. Blood and CSF culture testing rates during the pandemic were comparable to previous years. CONCLUSIONS: NPIs likely contributed to the decline in IBD incidence in the United States in 2020; observed declines were unlikely to be driven by reductions in testing.

This review summarizes the recent Global Meningococcal Initiative (GMI) regional meeting, which explored meningococcal disease in North America. Invasive meningococcal disease (IMD) cases are documented through both passive and active surveillance networks. IMD appears to be decreasing in many areas, such as the Dominican Republic (2016: 18 cases; 2021: 2 cases) and Panama (2008: 1 case/100,000; 2021: <0.1 cases/100,000); however, there is notable regional and temporal variation. Outbreaks persist in at-risk subpopulations, such as people experiencing homelessness in the US and migrants in Mexico. The recent emergence of β-lactamase-positive and ciprofloxacin-resistant meningococci in the US is a major concern. While vaccination practices vary across North America, vaccine uptake remains relatively high. Monovalent and multivalent conjugate vaccines (which many countries in North America primarily use) can provide herd protection. However, there is no evidence that group B vaccines reduce meningococcal carriage. The coronavirus pandemic illustrates that following public health crises, enhanced surveillance of disease epidemiology and catch-up vaccine schedules is key. Whole genome sequencing is a key epidemiological tool for identifying IMD strain emergence and the evaluation of vaccine strain coverage. The Global Roadmap on Defeating Meningitis by 2030 remains a focus of the GMI.

BACKGROUND: Recently, several invasive meningococcal disease (IMD) outbreaks caused by Neisseria meningitidis have occurred among people experiencing homelessness (PEH). However, overall IMD risk among PEH is not well described. We compared incidence and characteristics of IMD among PEH and persons not known to be experiencing homelessness (non-PEH) in the United States. METHODS: We analyzed 2016-2019 IMD data from the National Notifiable Diseases Surveillance System (NNDSS) and enhanced meningococcal disease surveillance. Incidence was calculated using U.S. census data and Point-in-Time counts from the U.S. Department of Housing and Urban Development. RESULTS: Of cases from states participating in enhanced surveillance during 2016-2019 (n = 1409), 45 (3.2%) cases occurred among PEH. Annual incidence was higher among PEH (2.12 cases/100,000) than non-PEH (0.11 cases/100,000; relative risk: 19.8, 95% CI: 14.8-26.7). Excluding outbreak-associated cases (PEH n = 18, 40%; non-PEH n = 98, 7.2%), incidence among PEH remained elevated compared to incidence in non-PEH (relative risk: 12.8, 95% CI: 8.8-18.8). Serogroup C was identified in 68.2% of PEH cases compared to 26.4% in non-PEH (p < 0.0001). CONCLUSIONS: PEH are at increased risk for IMD. Further assessment is needed to determine the feasibility and potential impact of meningococcal vaccination for PEH in the United States.

We describe cases of invasive meningococcal disease caused by nongroupable Neisseria meningitidis belonging to a novel phylogenetic clade associated with urethritis. Seven cases were identified, comprising 0.6% of sequenced invasive meningococcal disease isolates from 2013 to 2017. Five patients had a known or likely immunocompromising condition, including 2 with a complement deficiency.

BACKGROUND: Historically, antimicrobial resistance has been rare in US invasive meningococcal disease cases. METHODS: Meningococcal isolates (n=695) were collected through population-based surveillance, 2012-2016, and national surveillance, 2015-2016. Antimicrobial susceptibility was assessed by broth microdilution. Resistance mechanisms were characterized using whole genome sequencing. RESULTS: All isolates were susceptible to six antibiotics (cefotaxime, ceftriaxone, meropenem, rifampin, minocycline, and azithromycin). Approximately 25% were penicillin- or ampicillin-intermediate; among these, 79% contained mosaic penA gene mutations. Less than 1% of isolates were penicillin-, ampicillin-, ciprofloxacin-, or levofloxacin-resistant. CONCLUSION: Penicillin- and ampicillin-intermediate isolates were common, but resistance to clinically relevant antibiotics remained rare.

Meningococcal disease is a serious bacterial infection | caused by Neisseria meningitidis, usually presenting as | meningitis, bacteraemia, or both. Even with appropriate | treatment, the case fatality rate is approximately | 10–15%, and 10–20% of survivors have long-term | sequelae.1 N meningitidis colonises the oropharynx and | is spread through the respiratory secretions of patients | with meningococcal disease or asymptomatic carriers. In | many regions, including Europe, adolescents and young | adults have the highest carriage rates and are thus | considered to be the primary source of transmission to | other age groups.2

This review article incorporates information from the 4(th) Global Meningococcal Initiative summit meeting. Since the introduction of stringent COVID-19 infection control and lockdown measures globally in 2020, there has been an impact on IMD prevalence, surveillance, and vaccination compliance. Incidence rates and associated mortality fell across various regions during 2020. A reduction in vaccine uptake during 2020 remains a concern globally. In addition, several Neisseria meningitidis clonal complexes, particularly CC4821 and CC11, continue to exhibit resistance to antibiotics, with resistance to ciprofloxacin or beta-lactams mainly linked to modifications of gyrA or penA alleles, respectively. Beta-lactamase acquisition was also reported through horizontal gene transfer (bla(ROB-1)) involving other bacterial species. Despite the challenges over the past year, progress has also been made on meningococcal vaccine development, with several pentavalent (serogroups ABCWY and ACWYX) vaccines currently being studied in late-stage clinical trial programmes.

BACKGROUND: The Advisory Committee on Immunization Practices (ACIP) recommends routine vaccination with a quadrivalent meningococcal conjugate serogroup A,C,W,Y (MenACWY) vaccine at 11-12 years of age, with a booster dose at 16 years. ACIP also recommends meningococcal vaccination for persons at increased risk of meningococcal disease, including a 2-dose primary series and regular booster doses for persons at increased risk because of underlying medical conditions. U.S. cases of serogroup A, C, W, and Y meningococcal disease in persons previously vaccinated with MenACWY vaccine have not been systematically described since 2008. Characterization of these cases is important to understand potential factors leading to breakthrough disease. METHODS: We analyzed cases of serogroup A,C,W, and Y meningococcal disease reported through the National Notifiable Diseases Surveillance System (NNDSS) from 2014 through 2018. State health departments submitted additional information on risk factors and clinical course. RESULTS: During 2014-2018, 822 cases of serogroup A, C, W, and Y meningococcal disease were reported through NNDSS; 34 (4%) were in patients who previously received ≥ 1 dose of MenACWY vaccine. Twenty-three vaccinated patients were up-to-date on MenACWY vaccine per recommendations, and seven were not up-to-date; four were missing information on the number of doses received. Seventeen cases (50%) occurred > 3 years after the most recent dose. A significantly higher proportion of vaccinated patients were people living with HIV (PLWH) compared to unvaccinated patients. Eight of the 34 vaccinated patients were immunosuppressed, including five PLWH, one taking eculizumab, and two taking other immunosuppressive medications. The case fatality ratio did not differ between vaccinated and unvaccinated patients. CONCLUSIONS: Immunosuppression, incomplete vaccination, and waning immunity likely contributed to breakthrough cases of meningococcal disease among people who received MenACWY vaccine. Continued monitoring of serogroup A, C, W, and Y meningococcal disease in previously vaccinated persons will help inform meningococcal disease prevention efforts.

Since serogroup B meningococcal (MenB) vaccines became available in the United States, six serogroup B meningococcal disease cases have been reported in MenB-4C (n = 4) or MenB-FHbp (n = 2) recipients. Cases were identified and characterized through surveillance and health record review. All five available isolates were characterized using whole genome sequencing; four isolates (from MenB-4C recipients) were further characterized using flow cytometry, MenB-4C-induced serum bactericidal activity (SBA), and genetic Meningococcal Antigen Typing System (gMATS). Three patients were at increased meningococcal disease risk because of an outbreak or underlying medical conditions, and only four of the six patients had completed a full 2-dose MenB series. Isolates were available from 5 patients, and all contained sub-family A FHbp. The four isolates from MenB-4C recipients expressed NhbA but were mismatched for the other MenB-4C vaccine antigens. These four isolates were relatively resistant to MenB-4C-induced SBA, but predicted by gMATS to be covered. Overall, patient risk factors, incomplete vaccine series completion, waning immunity, and strain resistance to SBA likely contributed to disease in these six patients.

BACKGROUND: In the USA, COVID-19 vaccines became available in mid-December, 2020, with adults aged 65 years and older among the first groups prioritised for vaccination. We estimated the national-level impact of the initial phases of the US COVID-19 vaccination programme on COVID-19 cases, emergency department visits, hospital admissions, and deaths among adults aged 65 years and older. METHODS: We analysed population-based data reported to US federal agencies on COVID-19 cases, emergency department visits, hospital admissions, and deaths among adults aged 50 years and older during the period Nov 1, 2020, to April 10, 2021. We calculated the relative change in incidence among older age groups compared with a younger reference group for pre-vaccination and post-vaccination periods, defined by the week when vaccination coverage in a given age group first exceeded coverage in the reference age group by at least 1%; time lags for immune response and time to outcome were incorporated. We assessed whether the ratio of these relative changes differed when comparing the pre-vaccination and post-vaccination periods. FINDINGS: The ratio of relative changes comparing the change in the COVID-19 case incidence ratio over the post-vaccine versus pre-vaccine periods showed relative decreases of 53% (95% CI 50 to 55) and 62% (59 to 64) among adults aged 65 to 74 years and 75 years and older, respectively, compared with those aged 50 to 64 years. We found similar results for emergency department visits with relative decreases of 61% (52 to 68) for adults aged 65 to 74 years and 77% (71 to 78) for those aged 75 years and older compared with adults aged 50 to 64 years. Hospital admissions declined by 39% (29 to 48) among those aged 60 to 69 years, 60% (54 to 66) among those aged 70 to 79 years, and 68% (62 to 73), among those aged 80 years and older, compared with adults aged 50 to 59 years. COVID-19 deaths also declined (by 41%, 95% CI -14 to 69 among adults aged 65-74 years and by 30%, -47 to 66 among those aged ≥75 years, compared with adults aged 50 to 64 years), but the magnitude of the impact of vaccination roll-out on deaths was unclear. INTERPRETATION: The initial roll-out of the US COVID-19 vaccination programme was associated with reductions in COVID-19 cases, emergency department visits, and hospital admissions among older adults. FUNDING: None.

The Advisory Committee on Immunization Practices (ACIP) recommends that adolescents aged 11-12 years routinely receive tetanus, diphtheria, and acellular pertussis (Tdap); meningococcal conjugate (MenACWY); and human papillomavirus (HPV) vaccines. Catch-up vaccination is recommended for hepatitis B (HepB); hepatitis A (HepA); measles, mumps, and rubella (MMR); and varicella (VAR) vaccines for adolescents whose childhood vaccinations are not current. Adolescents are also recommended to receive a booster dose of MenACWY vaccine at age 16 years, and shared clinical decision-making is recommended for the serogroup B meningococcal vaccine (MenB) for persons aged 16-23 years (1). To estimate coverage with recommended vaccines, CDC analyzed data from the 2020 National Immunization Survey-Teen (NIS-Teen) for 20,163 adolescents aged 13-17 years.* Coverage with ≥1 dose of HPV vaccine increased from 71.5% in 2019 to 75.1% in 2020. The percentage of adolescents who were up to date(†) with HPV vaccination (HPV UTD) increased from 54.2% in 2019 to 58.6% in 2020. Coverage with ≥1 dose of Tdap, ≥1 dose (and among adolescents aged 17 years, ≥2 doses) of MenACWY remained similar to coverage in 2019 (90.1%, 89.3%, and 54.4% respectively). Coverage increased for ≥2 doses of HepA among adolescents aged 13-17 years and ≥1 dose of MenB among adolescents aged 17 years. Adolescents living below the federal poverty level(§) had higher HPV vaccination coverage than adolescents living at or above the poverty level. Adolescents living outside a metropolitan statistical area (MSA)(¶) had lower coverage with ≥1 MenACWY and ≥1 HPV dose, and a lower proportion being HPV UTD than adolescents in MSA principal cities. In 2020, the COVID-19 pandemic disrupted routine immunization services. Results from the 2020 NIS-Teen reflect adolescent vaccination coverage before the COVID-19 pandemic. The 2020 NIS-Teen data could be used to assess the impact of the COVID-19 pandemic on catch-up vaccination but not on routine adolescent vaccination because adolescents included in the survey were aged ≥13 years, past the age when most routine adolescent vaccines are recommended, and most vaccinations occurred before March 2020. Continued efforts to reach adolescents whose routine medical care has been affected by the COVID-19 pandemic are necessary to protect persons and communities from vaccine-preventable diseases and outbreaks.

Since 2010, the introduction of an effective serogroup A meningococcal conjugate vaccine has led to the near-elimination of invasive Neisseria meningitidis serogroup A disease in Africa's meningitis belt. However, a significant burden of disease and epidemics due to other bacterial meningitis pathogens remain in the region. High-quality surveillance data with laboratory confirmation is important to monitor circulating bacterial meningitis pathogens and design appropriate interventions, but complete testing of all reported cases is often infeasible. Here, we use case-based surveillance data from 5 countries in the meningitis belt to determine how accurately estimates of the distribution of causative pathogens would represent the true distribution under different laboratory testing strategies. Detailed case-based surveillance data was collected by the MenAfriNet surveillance consortium in up to 3 seasons from participating districts in 5 countries. For each unique country-season pair, we simulated the accuracy of laboratory surveillance by repeatedly drawing subsets of tested cases and calculating the margin of error of the estimated proportion of cases caused by each pathogen (the greatest pathogen-specific absolute error in proportions between the subset and the full set of cases). Across the 12 country-season pairs analyzed, the 95% credible intervals around estimates of the proportion of cases caused by each pathogen had median widths of ±0.13, ±0.07, and ±0.05, respectively, when random samples of 25%, 50%, and 75% of cases were selected for testing. The level of geographic stratification in the sampling process did not meaningfully affect accuracy estimates. These findings can inform testing thresholds for laboratory surveillance programs in the meningitis belt.

Meningococcal disease is a life-threatening illness caused by the human-restricted bacterium Neisseria meningitidis. Outbreaks in the USA involve at least two cases in an organization or community caused by the same serogroup within three months. Genome comparisons, including phylogenetic analysis and quantification of genome distances can provide confirmatory evidence of pathogen transmission during an outbreak. Interpreting genome distances depends on understanding their distribution both among isolates from outbreaks and among those not from outbreaks. Here, we identify outbreak strains based on phylogenetic relationships among 141 N. meningitidis isolates collected from 28 outbreaks in the USA during 2010-2017 and 1516 non-outbreak isolates collected through contemporaneous meningococcal surveillance. We show that genome distance thresholds based on the maximum SNPs and allele distances among isolates in the phylogenetically defined outbreak strains are sufficient to separate most pairs of non-outbreak isolates into separate strains. Non-outbreak isolate pairs that could not be distinguished from each other based on genetic distances were concentrated in the clonal complexes CC11, CC103, and CC32. Within each of these clonal complexes, phylodynamic analysis identified a group of isolates with extremely low diversity, collected over several years and multiple states. Clusters of isolates with low genetic diversity could indicate increased pathogen transmission, potentially resulting in local outbreaks or nationwide clonal expansions.

Carriage evaluations were conducted during 2015 to 2016 at two U.S. universities in conjunction with the response to disease outbreaks caused by Neisseria meningitidis serogroup B and at a university where outbreak and response activities had not occurred. All eligible students at the two universities received the serogroup B meningococcal factor H binding protein vaccine (MenB-FHbp); 5.2% of students (181/3,509) at one university received MenB-4C. A total of 1,514 meningococcal carriage isolates were obtained from 8,905 oropharyngeal swabs from 7,001 unique participants. Whole-genome sequencing data were analyzed to understand MenB-FHbp's impact on carriage and antigen genetic diversity and distribution. Of 1,422 isolates from carriers with known vaccination status (726 [51.0%] from MenB-FHbp-vaccinated, 42 [3.0%] from MenB-4C-vaccinated, and 654 [46.0%] from unvaccinated participants), 1,406 (98.9%) had intact fHbp alleles (716 from MenB-FHbp-vaccinated participants). Of 726 isolates from MenB-FHbp-vaccinated participants, 250 (34.4%) harbored FHbp peptides that may be covered by MenB-FHbp. Genogroup B was detected in 122/1,422 (8.6%) and 112/1,422 (7.9%) isolates from MenB-FHbp-vaccinated and unvaccinated participants, respectively. FHbp subfamily and peptide distributions between MenB-FHbp-vaccinated and unvaccinated participants were not statistically different. Eighteen of 161 MenB-FHbp-vaccinated repeat carriers (11.2%) acquired a new strain containing one or more new vaccine antigen peptides during multiple rounds of sample collection, which was not statistically different (P = 0.3176) from the unvaccinated repeat carriers (1/30; 3.3%). Our findings suggest that lack of MenB vaccine impact on carriage was not due to missing the intact fHbp gene; MenB-FHbp did not affect antigen genetic diversity and distribution during the study period.IMPORTANCE The impact of serogroup B meningococcal (MenB) vaccines on carriage is not completely understood. Using whole-genome sequencing data, we assessed the diversity and distribution of MenB vaccine antigens (particularly FHbp) among 1,514 meningococcal carriage isolates recovered from vaccinated and unvaccinated students at three U.S. universities, two of which underwent MenB-FHbp mass vaccination campaigns following meningococcal disease outbreaks. The majority of carriage isolates recovered from participants harbored intact fHbp genes, about half of which were recovered from MenB-FHbp-vaccinated participants. The distribution of vaccine antigen peptides was similar among carriage isolates recovered from vaccinated and unvaccinated participants, and almost all strains recovered from repeat carriers retained the same vaccine antigen profile, suggesting insignificant vaccine selective pressure on the carriage population in these universities.