This article summarizes what is currently known about the 2019 novel coronavirus and offers interim guidance.

In October 2020, the Advisory Committee on Immunization Practices (ACIP) voted to approve the Recommended Adult Immunization Schedule for Ages 19 Years or Older, United States, 2021. Following Emergency Use Authorization of Pfizer-BioNTech COVID-19 vaccine by the U.S. Food and Drug Administration, ACIP issued an interim recommendation at its 12 December 2020 emergency meeting for use of Pfizer-BioNTech COVID-19 vaccine in persons aged 16 years or older (1). In addition, ACIP approved an amendment to include COVID-19 vaccine recommendations in the child and adolescent and adult immunization schedules. Following Emergency Use Authorization of Moderna COVID-19 vaccine by the U.S. Food and Drug Administration, ACIP issued an interim recommendation at its 19 December 2020 emergency meeting for use of Moderna COVID-19 vaccine in persons aged 18 years or older (2). The 2021 adult immunization schedule, available at www.cdc.gov/vaccines/schedules/hcp/imz/adult.html, summarizes ACIP recommendations in 2 tables and accompanying notes (Figure). The full ACIP recommendations for each vaccine are available at www.cdc.gov/vaccines/hcp/acip-recs/index.html. The 2021 schedule has also been approved by the director of the Centers for Disease Control and Prevention (CDC) and by the American College of Physicians (www.acponline.org), the American Academy of Family Physicians (www.aafp.org), the American College of Obstetricians and Gynecologists (www.acog.org), the American College of Nurse-Midwives (www.midwife.org), and the American Academy of Physician Assistants

As the world follows the progress of vaccine uptake in the fight against COVID-19, we are once again reminded of how vaccines can impact our personal health and the health of our communities. But even as we look to safe and effective vaccines as the best way forward, vaccine hesitancy already threatens our ability to effectively protect communities from vaccine-preventable diseases.1 Vaccine hesitancy is nothing new; however, the speed of information sharing in our global community has accelerated the spread of both accurate vaccine information and vaccine misinformation. Recent measles outbreaks in the United States have demonstrated how the spread of misinformation has a real-world impact, particularly in close-knit communities.2 Persistent underimmunization—associated with factors like vaccine hesitancy and health care access—challenge us to make sure that vaccine-preventable infections like measles, pertussis, and human papillomavirus do not continue to cause preventable illness and death.

In December 2020, two COVID-19 vaccines (Pfizer-BioNTech and Moderna) were authorized for emergency use in the United States for the prevention of coronavirus disease 2019 (COVID-19).* Because of limited initial vaccine supply, the Advisory Committee on Immunization Practices (ACIP) prioritized vaccination of health care personnel(†) and residents and staff members of long-term care facilities (LTCF) during the first phase of the U.S. COVID-19 vaccination program (1). Both vaccines require 2 doses to complete the series. Data on vaccines administered during December 14, 2020-January 14, 2021, and reported to CDC by January 26, 2021, were analyzed to describe demographic characteristics, including sex, age, and race/ethnicity, of persons who received ≥1 dose of COVID-19 vaccine (i.e., initiated vaccination). During this period, 12,928,749 persons in the United States in 64 jurisdictions and five federal entities(§) initiated COVID-19 vaccination. Data on sex were reported for 97.0%, age for 99.9%, and race/ethnicity for 51.9% of vaccine recipients. Among persons who received the first vaccine dose and had reported demographic data, 63.0% were women, 55.0% were aged ≥50 years, and 60.4% were non-Hispanic White (White). More complete reporting of race and ethnicity data at the provider and jurisdictional levels is critical to ensure rapid detection of and response to potential disparities in COVID-19 vaccination. As the U.S. COVID-19 vaccination program expands, public health officials should ensure that vaccine is administered efficiently and equitably within each successive vaccination priority category, especially among those at highest risk for infection and severe adverse health outcomes, many of whom are non-Hispanic Black (Black), non-Hispanic American Indian/Alaska Native (AI/AN), and Hispanic persons (2,3).

In the 10 months since the first confirmed case of coronavirus disease 2019 (COVID-19) was reported in the United States on January 20, 2020 (1), approximately 13.8 million cases and 272,525 deaths have been reported in the United States. On October 30, the number of new cases reported in the United States in a single day exceeded 100,000 for the first time, and by December 2 had reached a daily high of 196,227.* With colder weather, more time spent indoors, the ongoing U.S. holiday season, and silent spread of disease, with approximately 50% of transmission from asymptomatic persons (2), the United States has entered a phase of high-level transmission where a multipronged approach to implementing all evidence-based public health strategies at both the individual and community levels is essential. This summary guidance highlights critical evidence-based CDC recommendations and sustainable strategies to reduce COVID-19 transmission. These strategies include 1) universal face mask use, 2) maintaining physical distance from other persons and limiting in-person contacts, 3) avoiding nonessential indoor spaces and crowded outdoor spaces, 4) increasing testing to rapidly identify and isolate infected persons, 5) promptly identifying, quarantining, and testing close contacts of persons with known COVID-19, 6) safeguarding persons most at risk for severe illness or death from infection with SARS-CoV-2, the virus that causes COVID-19, 7) protecting essential workers with provision of adequate personal protective equipment and safe work practices, 8) postponing travel, 9) increasing room air ventilation and enhancing hand hygiene and environmental disinfection, and 10) achieving widespread availability and high community coverage with effective COVID-19 vaccines. In combination, these strategies can reduce SARS-CoV-2 transmission, long-term sequelae or disability, and death, and mitigate the pandemic's economic impact. Consistent implementation of these strategies improves health equity, preserves health care capacity, maintains the function of essential businesses, and supports the availability of in-person instruction for kindergarten through grade 12 schools and preschool. Individual persons, households, and communities should take these actions now to reduce SARS-CoV-2 transmission from its current high level. These actions will provide a bridge to a future with wide availability and high community coverage of effective vaccines, when safe return to more everyday activities in a range of settings will be possible.

Globally, approximately 170,000 confirmed cases of coronavirus disease 2019 (COVID-19) caused by the 2019 novel coronavirus (SARS-CoV-2) have been reported, including an estimated 7,000 deaths in approximately 150 countries (1). On March 11, 2020, the World Health Organization declared the COVID-19 outbreak a pandemic (2). Data from China have indicated that older adults, particularly those with serious underlying health conditions, are at higher risk for severe COVID-19-associated illness and death than are younger persons (3). Although the majority of reported COVID-19 cases in China were mild (81%), approximately 80% of deaths occurred among adults aged ≥60 years; only one (0.1%) death occurred in a person aged ≤19 years (3). In this report, COVID-19 cases in the United States that occurred during February 12-March 16, 2020 and severity of disease (hospitalization, admission to intensive care unit [ICU], and death) were analyzed by age group. As of March 16, a total of 4,226 COVID-19 cases in the United States had been reported to CDC, with multiple cases reported among older adults living in long-term care facilities (4). Overall, 31% of cases, 45% of hospitalizations, 53% of ICU admissions, and 80% of deaths associated with COVID-19 were among adults aged ≥65 years with the highest percentage of severe outcomes among persons aged ≥85 years. In contrast, no ICU admissions or deaths were reported among persons aged ≤19 years. Similar to reports from other countries, this finding suggests that the risk for serious disease and death from COVID-19 is higher in older age groups.

An outbreak of novel coronavirus (2019-nCoV) that began in Wuhan, China, has spread rapidly, with cases now confirmed in multiple countries. We report the first case of 2019-nCoV infection confirmed in the United States and describe the identification, diagnosis, clinical course, and management of the case, including the patient's initial mild symptoms at presentation with progression to pneumonia on day 9 of illness. This case highlights the importance of close coordination between clinicians and public health authorities at the local, state, and federal levels, as well as the need for rapid dissemination of clinical information related to the care of patients with this emerging infection.

BACKGROUND: From January-July 2014, >46,000 unaccompanied children (UC) from Central America crossed the U.S.-Mexico border. In June-July, UC aged 9-17 years in four shelters and a processing center in four U.S. states were hospitalized with acute respiratory illness. We conducted a multistate investigation to interrupt disease transmission. METHODS: Medical charts were abstracted for hospitalized UC. Non-hospitalized UC with influenza-like illness were interviewed, and nasopharyngeal and oropharyngeal swabs for PCR-based detection of respiratory pathogens were collected. Nasopharyngeal swabs were used to assess pneumococcal colonization in symptomatic and asymptomatic UC. Pneumococcal blood isolates from hospitalized UC and nasopharyngeal isolates were characterized by serotyping (Quellung) and whole-genome sequencing. RESULTS: Among the 15 hospitalized UC, 4 (44%) of 9 tested positive for influenza viruses, and 6 (43%) of 14 with blood cultures grew pneumococcus, all serotype 5. Among 48 non-hospitalized children with influenza-like illness, >1 respiratory pathogen was identified in 46 (96%). Among 774 non-hospitalized UC, 185 (24%) yielded pneumococcus, and 70 (38%) were serotype 5. UC who transferred through the processing center were more likely than others to be colonized with serotype 5 (OR 3.8; 95% CI, 2.1-6.9). Analysis of the core pneumococcal genomes detected two related, yet independent, clusters. No pneumococcus cases were reported after pneumococcal and influenza immunization campaigns were implemented. CONCLUSIONS: This outbreak of respiratory disease was due to multiple pathogens, including Streptococcus pneumoniae serotype 5 and influenza viruses. Pneumococcal and influenza vaccinations prevented further transmission. Future efforts to prevent similar outbreaks will benefit from use of both vaccines.

BACKGROUND: Antimicrobial treatment and chemoprophylaxis of patients and their close contacts is critical to reduce the morbidity and mortality and prevent secondary cases of meningococcal disease. Through the 1990's, the prevalence of antimicrobial resistance to commonly used antimicrobials among Neisseria meningitidis was low in the United States. Susceptibility testing was performed to ascertain whether the proportions of isolates with reduced susceptibility to antimicrobials commonly used for N meningitidis have increased since 2004 in the United States. METHODS: Antimicrobial susceptibility testing was performed by broth microdilution on 466 isolates of N meningitidis collected in 2004, 2008, 2010, and 2011 from an active, population-based surveillance system for susceptibility to ceftriaxone, ciprofloxacin, penicillin G, rifampin, and azithromycin. The molecular mechanism of reduced susceptibility was investigated for isolates with intermediate or resistant phenotypes. RESULTS: All isolates were susceptible to ceftriaxone and azithromycin, 10.3% were penicillin G intermediate (range, 8% in 2008-16.7% in 2010), and <1% were ciprofloxacin, rifampin, or penicillin G resistant. Of the penicillin G intermediate or resistant isolates, 63% contained mutations in the penA gene associated with reduced susceptibility to penicillin G. All ciprofloxacin-resistant isolates contained mutations in the gyrA gene associated with reduced susceptibility. CONCLUSIONS:. Resistance of N meningitidis to antimicrobials used for empirical treatment of meningitis in the United States has not been detected, and resistance to penicillin G and chemoprophylaxis agents remains uncommon. Therapeutic agent recommendations remain valid. Although periodic surveillance is warranted to monitor trends in susceptibility, routine clinical testing may be of little use.

BACKGROUND: Meningococcal conjugate vaccines (MenACWY) against serogroups A, C, W and Y are recommended for routine use in adolescents aged 11-18 years. Impact of these vaccines on meningococcal population structure in the US remained to be evaluated. METHODS: Meningococcal isolates from 2006-10 (post-MenACWY) collected through Active Bacterial Core surveillance (ABCs) were characterized; serogroup distribution and molecular features of these isolates were compared to previously published data on ABCs isolates from 2000-05 (pre-MenACWY). p values were generated using chi-squared statistics and exact methods. RESULTS: There was a significant change (p<0.05) in serogroup distribution among all age groups between the two periods. A small proportion of isolates has shown evidence of capsular switching in both periods. Between the two periods, significant changes were observed in the distribution of PorA, FetA, and strain genotypes among vaccine and non-vaccine serogroups. CONCLUSIONS: The population structure of U.S. meningococcal isolates is dynamic; some changes occurred over time but the basic structure remained. Vaccine-induced serogroup replacement was not observed, although a small proportion of isolates had undergone capsule switching possibly driven by non-vaccine mediated selection. Changes in the distribution of molecular features are likely due to horizontal gene transfer and changes in serogroup distribution.

BACKGROUND: The detection of meningococcal outbreaks relies on serogrouping and epidemiologic definitions. Advances in molecular epidemiology have improved the ability to distinguish unique Neisseria meningitidis strains, enabling the classification of isolates into clones. Around 98% of meningococcal cases in the United States are believed to be sporadic. METHODS: Meningococcal isolates from 9 Active Bacterial Core surveillance sites throughout the United States from 2000 through 2005 were classified according to serogroup, multilocus sequence typing, and outer membrane protein (porA, porB, and fetA) genotyping. Clones were defined as isolates that were indistinguishable according to this characterization. Case data were aggregated to the census tract level and all non-singleton clones were assessed for non-random spatial and temporal clustering using retrospective space-time analyses with a discrete Poisson probability model. RESULTS: Among 1,062 geocoded cases with available isolates, 438 unique clones were identified, 78 of which had ≥2 isolates. 702 cases were attributable to non-singleton clones, accounting for 66.0% of all geocoded cases. 32 statistically significant clusters comprised of 107 cases (10.1% of all geocoded cases) were identified. Clusters had the following attributes: included 2 to 11 cases; 1 day to 33 months duration; radius of 0 to 61.7 km; and attack rate of 0.7 to 57.8 cases per 100,000 population. Serogroups represented among the clusters were: B (n = 12 clusters, 45 cases), C (n = 11 clusters, 27 cases), and Y (n = 9 clusters, 35 cases); 20 clusters (62.5%) were caused by serogroups represented in meningococcal vaccines that are commercially available in the United States. CONCLUSIONS: Around 10% of meningococcal disease cases in the U.S. could be assigned to a geotemporal cluster. Molecular characterization of isolates, combined with geotemporal analysis, is a useful tool for understanding the spread of virulent meningococcal clones and patterns of transmission in populations.

BACKGROUND AND OBJECTIVES: We investigated a pertussis outbreak characterized by atypical cases, confirmed by polymerase chain reaction (PCR) alone at a single laboratory, which persisted despite high vaccine coverage and routine control measures. We aimed to determine whether Bordetella pertussis was the causative agent and advise on control interventions. METHODS: We conducted case ascertainment, confirmatory testing for pertussis and other pathogens, and an assessment for possible sources of specimen contamination, including a survey of clinic practices, sampling clinics for B pertussis DNA, and review of laboratory quality indicators. RESULTS: Between November 28, 2008, and September 4, 2009, 125 cases were reported, of which 92 (74%) were PCR positive. Cases occurring after April 2009 (n = 79; 63%) had fewer classic pertussis symptoms (63% vs 98%; P < .01), smaller amounts of B pertussis DNA (mean PCR cycle threshold value: 40.9 vs 33.1; P < .01), and a greater proportion of PCR-positive results (34% vs 6%; P < .01). Cultures and serology for B pertussis were negative. Other common respiratory pathogens were detected. We identified factors that likely resulted in specimen contamination at the point of collection: environmentally present B pertussis DNA in clinics from vaccine, clinic standard specimen collection practices, use of liquid transport medium, and lack of clinically relevant PCR cutoffs. CONCLUSIONS: A summer pertussis pseudo-outbreak, multifactorial in cause, likely occurred. Recommendations beyond standard practice were made to providers on specimen collection and environmental cleaning, and to laboratories on standardizing PCR protocols and reporting results, to minimize false-positive results from contaminated clinical specimens.

During the past decade, monovalent serogroup C and quadrivalent (serogroups A, C, W135, Y) meningococcal vaccination programs have been introduced in multiple industrialized countries. Many of these programs have been successful in reducing the burden of disease due to vaccine-preventable serogroups of Neisseria meningitidis in target age groups. As a result, disease burden in these countries has decreased and is primarily serogroup B, which is not vaccine preventable. Despite the success of these programs, meningococcal disease continues to occur and there is always concern that serogroup C organisms will adapt their virulence mechanisms to escape pressure from vaccination. This review highlights the current epidemiology of meningococcal disease in Europe and United States, as well as genetic mechanisms that may affect virulence of serogroup C strains and effectiveness of new vaccines.

Neisseria meningitidis (Nm) serogroups B, C and Y are the major causes of meningococcal diseases in the United States. NmB accounts for approximately 1/3 of the disease but no licensed vaccine is yet available. Two candidate vaccines are being developed specifically to target NmB, but may also provide protection against other serogroups. To assess the potential impact of these vaccines on NmB and other serogroups causing disease in the US, we determined the prevalence, genetic diversity and epidemiological characteristics of three candidate antigen genes in Nm isolates collected through Active Bacterial Core surveillance (ABCs), a population-based active surveillance program. fHbp was detected in all NmB, NmY and NmW135 isolates. Eleven NmC isolates contain fHbp with a single base-pair deletion creating a frame shift in the C-terminal region. Among NmB, 59% were fHbp subfamily/variant B/v1 and 41% A/v2-3. Among NmC and NmY, 39% and 3% were B/v1, respectively. nadA was detected in 39% of NmB, 61% of NmC and 4% of NmY. Among isolates tested, nhbA was present in all NmB and 96% of non-B. For the subset of strains sequenced for NadA and NhbA, pairwise identity was greater than 93% and 78%, respectively. The proportion of FHbp subfamily/variant was different between ABCs site and year, but no linear temporal trend was observed. Although assessment of the vaccine coverage also requires understanding of the antigen expression and the ability to induce bactericidal activity, our finding that all isolates contain one or more antigen genes suggests these vaccines may protect against multiple Nm serogroups.

Since the implementation of Haemophilus influenzae (Hi) serotype b vaccine, other serotypes and non-typeable strains have taken on greater importance as a cause of Hi diseases. A rapid and accurate method is needed to detect all Hi regardless of the encapsulation status. We developed 2 real-time PCR (rt-PCR) assays to detect specific regions of the protein D gene (hpd). Both hpd assays are very specific and sensitive for detection of Hi. Of the 63 non-Hi isolates representing 21 bacterial species, none was detected by the hpd #1 assay, and only one of 2 H. aphrophilus isolates was detected by the hpd #3 assay. The hpd #1 and #3 assays detected 97% (229/237) and 99% (234/237) of Hi isolates, respectively, and were superior for detection of both typeable and non-typeable Hi isolates, as compared to previously developed rt-PCR targeting ompP2 or bexA. The diagnostic sensitivity and specificity of these rt-PCR assays were assessed on cerebrospinal fluid specimens collected as part of meningitis surveillance in Ulaanbaatar, Mongolia. The etiology (Neisseria meningitidis, Hi, and Streptococcus pneumoniae) of 111 suspected meningitis cases was determined by conventional methods (culture and latex agglutination), previously developed rt-PCR assays, and the new hpd assays. The rt-PCR assays were more sensitive for detection of meningitis pathogens than other classical methods and improved detection from 50% (56/111) to 75% (83/111). The hpd #3 assay identified a non-b Hi that was missed by the bexA assay and other methods. A sensitive rt-PCR assay to detect both typeable and non-typeable Hi is a useful tool for improving Hi disease surveillance especially after Hib vaccine introduction.