BACKGROUND: Widespread outbreaks of person-to-person transmitted hepatitis A virus (HAV), particularly among people who inject drugs (PWID), continue across the United States and globally. However, the herd immunity threshold and vaccination coverage required to prevent outbreaks are unknown. We used surveillance data and dynamic modeling to estimate herd immunity thresholds among PWID in 16 US states. METHODS: We used a previously published dynamic model of HAV transmission calibrated to surveillance data from outbreaks involving PWID in 16 states. Using state-level calibrated models, we estimated the basic reproduction number (R0) and herd immunity threshold for PWID in each state. We performed a meta-analysis of herd immunity thresholds to determine the critical vaccination coverage required to prevent most HAV outbreaks among PWID. RESULTS: Estimates of R0 for HAV infection ranged from 2.2 (95% confidence interval [CI], 1.9-2.5) for North Carolina to 5.0 (95% CI, 4.5-5.6) for West Virginia. Corresponding herd immunity thresholds ranged from 55% (95% CI, 47%-61%) for North Carolina to 80% (95% CI, 78%-82%) for West Virginia. Based on the meta-analysis, we estimated a pooled herd immunity threshold of 64% (95% CI, 61%-68%; 90% prediction interval, 52%-76%) among PWID. Using the prediction interval upper bound (76%) and assuming 95% vaccine efficacy, we estimated that vaccination coverage of 80% could prevent most HAV outbreaks. CONCLUSIONS: Hepatitis A vaccination programs in the United States may need to achieve vaccination coverage of at least 80% among PWID in order to prevent most HAV outbreaks among this population.

OBJECTIVES: Hepatitis C virus (HCV) infection is the most common bloodborne infection in the United States. We assessed trends in HCV testing, infection, and surveillance cases among US adults. METHODS: We used Quest Diagnostics data from 2013-2021 to assess trends in the numbers tested for HCV antibody and proportion of positivity for HCV antibody and HCV RNA. We also assessed National Notifiable Diseases Surveillance System 2013-2020 data for trends in the number and proportion of hepatitis C cases. We applied joinpoint regression for trends testing. RESULTS: Annual HCV antibody testing increased from 1.7 million to 4.8 million from 2013 to 2021, and the positivity proportion declined (average, 0.2% per year) from 5.5% to 3.7%. The greatest percentage-point increase in HCV antibody testing occurred in hospitals and substance use disorder treatment facilities and among addiction medicine providers. HCV RNA positivity was stable at about 60% in 2013-2015 and declined to 41.0% in 2021 (2015-2021 average, -3.2% per year). Age-specific HCV RNA positivity was highest among people aged 40-59 years during 2013-2015 and among people aged 18-39 years during 2016-2021. The number of reported hepatitis C cases (acute and chronic) declined from 179 341 in 2015 to 105 504 in 2020 (average decline, -13 177 per year). The proportion of hepatitis C cases among those aged 18-39 years increased by an average of 1.4% per year during 2013-2020; among individuals aged 40-59 years, it decreased by an average of 2.3% per year during 2013-2018. CONCLUSIONS: HCV testing increased, suggesting improved universal screening. Various data sources are valuable for monitoring elimination progress.

OBJECTIVES: The incidence of hepatitis A declined in the United States following the introduction of hepatitis A vaccines, before increasing in the setting of recent widespread outbreaks associated with person-to-person transmission. We describe the hepatitis A epidemiology in the United States, identify susceptible populations over time, and demonstrate the need for improved hepatitis A vaccination coverage, especially among adults at increased risk for hepatitis A. METHODS: We calculated the hepatitis A incidence rates for sociodemographic characteristics and percentages for risk factors and clinical outcomes for hepatitis A cases reported to the National Notifiable Diseases Surveillance System during 1990-2020. We generated nationally representative estimates and 95% CIs of hepatitis A seroprevalence during 1976-March 2020 and self-reported hepatitis A vaccination coverage during 1999-March 2020 for the noninstitutionalized civilian US population using data from the National Health and Nutrition Examination Survey. RESULTS: Overall, the rate per 100 000 population of reported cases of hepatitis A virus infection in the United States declined 17.3-fold, from 10.4 during 1990-1998 to 0.6 during 2007-2015, and then increased to 2.8 during 2016-2020. The overall hepatitis A seroprevalence in the United States increased from 38.2% (95% CI, 36.2%-40.1%) during 1976-1980 to 47.3% (95% CI, 45.4%-49.2%) during 2015-March 2020. The prevalence of self-reported hepatitis A vaccination coverage in the United States increased more than 2.5-fold, from 16.3% (95% CI, 15.0%-17.7%) during 1999-2006 to 41.9% (95% CI, 40.2%-43.7%) during 2015-March 2020. CONCLUSIONS: Hepatitis A epidemiology in the United States changed substantially during 1976-2020. Improved vaccination coverage, especially among adults recommended for vaccination by the Advisory Committee on Immunization Practices, is vital to stop current hepatitis A outbreaks associated with person-to-person transmission in the United States and prevent similar future recurrences.

Adults at increased risk for hepatitis B virus (HBV) infection are recommended to receive vaccination. We conducted a cost utility analysis to evaluate approaches for implementing that recommendation in selected high-risk settings: community outreach events with a large proportion of immigrants, syringe service programs, substance use treatment centers, sexually transmitted infection (STI) clinics, tuberculosis (TB) clinics, and jails. We utilized a decision tree framework with a Markov disease progression model to compare quality adjusted life-years and cost in 2021 United States dollars from four strategies: a 3-dose vaccination regimen with prevaccination screening and testing (PVST; baseline comparison); PVST at the initial encounter followed by a 2-dose series (Intervention 1); PVST with the first dose of a 2-dose vaccination series at the initial encounter (Intervention 2); and a 2-dose vaccination series without PVST (Intervention 3). In all settings, Intervention 1 resulted in worse health outcomes compared to the baseline strategy. Intervention 2 averted incident chronic HBV infections in all settings (range -9.4% in TB clinics, -14.8% in syringe service programs) and was a cost-saving approach in settings with higher risk of infection (i.e. jails, -$266 per person; syringe service programs, -$597; substance use treatment centers, -$130). Providing a 2-dose vaccination series without any screening (Intervention 3) averted incident HBV infections and was cost-saving in all settings, but resulted in more HBV-related deaths in settings with higher HBV prevalence. These results demonstrate a 2-dose vaccine series is a cost-effective approach in these high impact settings, even if prevaccination testing is not possible.

BACKGROUND: Vaccine-hesitant persons who inject drugs are at increased risk for several vaccine-preventable diseases. However, vaccination rates among this population remain low. While syringe services programs (SSPs) are places where persons who inject drugs feel comfortable accessing services, few offer vaccination services. This study describes facilitators and barriers to vaccination at SSPs. METHODS: We used convenience sampling to conduct semi-structured, qualitative in-depth interviews with 21 SSPs in the USA from June to August 2021. Interview questions asked SSPs about their perceptions, priorities, barriers, facilitators, and the effects of partnerships and policies on vaccine administration. We used deductive thematic analysis to identify the main themes. RESULTS: Eight (n = 8) SSPs offered vaccinations, and thirteen (n = 13) did not offer vaccinations. Most SSPs believed offering vaccination services was important, although addressing SSP participants' immediate needs often took precedence. Staffing, physical space, and logistical issues were the most common barriers to vaccine administration reported by SSPs, followed by SSP participant-related barriers. Facilitators of vaccine administration included access to a tracking system, partnering with agencies or other organizations providing vaccines, and having a licensed vaccination provider on-site. Partnerships provided SSPs opportunities to expand capacity but could also restrict how SSPs operate. Recommended policy changes to facilitate vaccine administration included subsidizing the cost of vaccinations and addressing restrictions around who could administer vaccinations. CONCLUSIONS: Increasing the availability of vaccination services at SSPs requires addressing the varying capacity needs of SSPs, such as tracking systems, licensed vaccinators, and free or low-cost vaccination supplies. While these needs can be met through partnerships and supportive policies, both must consider and reflect cultural competence around the lived experiences of persons who inject drugs.

BACKGROUND: People who use drugs are at increased risk for hepatitis A virus infection. Since 1996, the Advisory Committee on Immunization Practices has recommended hepatitis A vaccination for people who use drugs. Since 2016, the U.S. has experienced widespread hepatitis A outbreaks associated with person-to-person transmission. PURPOSE: To describe the prevalence of drug use, route of use, and drugs used among hepatitis A outbreak-associated patients. METHODS: State outbreak and medical records were reviewed to describe the prevalence, type, and route of drug use among a random sample of 812 adult outbreak-associated hepatitis A patients from Kentucky, Michigan, and West Virginia during 2016-2019. Differences in drug-use status were analyzed by demographic and risk-factor characteristics using the X (2) test. RESULTS: Among all patients, residents of Kentucky (55.6%), Michigan (51.1%), and West Virginia (60.1%) reported any drug use, respectively. Among patients that reported any drug use, methamphetamine was the most frequently reported drug used in Kentucky (42.3%) and West Virginia (42.1%); however, opioids were the most frequently reported drug used in Michigan (46.8%). Hepatitis A patients with documented drug use were more likely (p<0.05) to be experiencing homelessness/unstable housing, have been currently or recently incarcerated, and be aged 18-39 years compared to those patients without documented drug use. IMPLICATIONS: Drug use was prevalent among person-to-person hepatitis A outbreak-associated patients, and more likely among younger patients and patients experiencing homelessness or incarceration. Increased hepatitis A vaccination coverage is critical to prevent similar outbreaks in the future.

BACKGROUND: Syringe services programs (SSPs) are an important venue for reaching people who inject drugs (PWID) to offer preventive services; however, not all SSPs offer vaccinations. We aimed to describe barriers and opportunities for SSPs to offer vaccinations. METHODS: During June-August 2021, we conducted a descriptive, cross-sectional survey of SSP providers in the United States. SSPs were recruited from national listservs using purposive sampling to ensure geographic diversity. The survey included questions about SSP characteristics, client demographics, existing vaccination resources, resource needs, and staff perspectives on client vaccination barriers. Statistical comparisons were made using Pearson's chi-square test. RESULTS: In total, 105 SSPs from 34 states responded to the survey; 46 SSPs (43.8%) offered on-site vaccinations. SSPs without on-site vaccinations were more likely operated by community-based organizations (81.4% vs 30.4%, p < 0.001) in urban areas (71.4% vs 40.0%, p = 0.002) than SSPs offering on-site vaccinations. The most common staffing need was for personnel licensed to administer vaccines (74/98, 75.5%). Over half of SSPs reported vaccine supply, administration supplies, storage equipment, and systems to follow-up clients for multidose series as important resource needs. The most common resource need was for reminder/recall systems for vaccines with multidose series (75/92, 81.5%). Vaccine safety concerns (92/95, 96.8%) and competing priorities (92/96, 95.8%) were the most common staff-reported client barriers to vaccinations. CONCLUSIONS: Addressing missed opportunities for offering vaccinations to PWID who use SSPs will require increased numbers of on-site personnel licensed to administer vaccines and additional training, vaccination supplies, and storage and handling equipment.

Hepatitis B (HepB) vaccines have demonstrated safety, immunogenicity, and efficacy during the past 4 decades (1,2). However, vaccination coverage among adults has been suboptimal, limiting further reduction in hepatitis B virus (HBV) infections in the United States. This Advisory Committee on Immunization Practices (ACIP) recommendation expands the indicated age range for universal HepB vaccination to now include adults aged 19-59 years. Removing the risk factor assessment previously recommended to determine vaccine eligibility in this adult age group (2) could increase vaccination coverage and decrease hepatitis B cases.

BACKGROUND: The duration of protection from hepatitis B vaccination in children and adults is not known. In 1981, we used three doses of plasma-derived hepatitis B vaccine to immunize a cohort of 1578 Alaska Native adults and children from 15 Alaska communities who were 6 months or older. METHODS: We tested persons for anti-HBs levels 35 years after receiving the primary series. Those with levels <10 mIU/ml received 1 booster dose of recombinant hepatitis B vaccine 2-4 weeks later and were then evaluated on the basis of anti-HBs measurements 30 days post-booster. RESULTS: Among the 320 recruited, 112 persons had not participated in the 22 nor 30-year follow-up study (Group 1) and 208 persons had participated but were not given an HBV booster dose (Group 2). Among the 112 persons in Group 1 who responded to the original primary series, 53 (47.3%) had an anti-HBs level ≥10 mIU/ml. Among group 1, 73.7% (28/38) of persons available for a booster dose responded to it with an anti-HBs level ≥10 mIU/ml at 30 days. Initial anti-HBs level after the primary series was correlated with higher anti-HBs levels at 35 years. Among 8 persons who tested positive for anti-HBc, none tested positive for HBsAg nor HBV DNA. CONCLUSIONS: Based on anti-HBs level ≥10 mIU/ml at 35 years and a 73.7% booster dose response, we estimate 86% of participants had evidence of protection 35 years later. Booster doses are not needed in the general population at this time.

BACKGROUND: Although effective against hepatitis B virus (HBV) infection, hepatitis B (HepB) vaccination is only recommended for infants, children and adults at higher risk. We conducted an economic evaluation of universal HepB vaccination among US adults. METHODS: Using a decision analytic model with Markov disease progression, we compared current vaccination recommendations (baseline) with either 3-dose or 2-dose universal HepB vaccination (intervention strategies). In simulated modeling of one million adults distributed by age and risk groups, we quantified health benefits (quality-adjusted life years, QALYs) and costs for each strategy. Multivariable probabilistic sensitivity analyses identified key inputs. All costs reported in 2019 US dollars. RESULTS: With incremental base-case vaccination coverage up to 50% among persons at lower risk and 0% increment among persons at higher risk, each of two intervention strategies averted nearly one quarter of acute HBV infections (3-dose strategy: 24.8%; 2-dose strategy: 24.6%). Societal incremental cost per QALY gained of $152,722 (Interquartile range: $119,113, $235,086) and $155,429 (Interquartile range: $120,302, $242,226) were estimated for 3-dose and 2-dose strategies, respectively. Risk of acute HBV infection showed the strongest influence. CONCLUSIONS: Universal adult vaccination against HBV may be an appropriate strategy for reducing HBV incidence and improving resulting health outcomes.

BACKGROUND: Between September 2017 and June 2019, an outbreak of hepatitis A virus (HAV) occurred in Louisville, Kentucky, resulting in 501 cases and 6 deaths, predominantly among persons who experience homelessness or who use drugs (PEH/PWUD). The critical vaccination threshold (V(c)) required to achieve herd immunity in this population is unknown. We investigated V(c) and vaccination impact using epidemic modeling. METHODS: To determine which population subgroups had high infection risks, we employed a technique based on comparing the proportion of cases arising before and after the epidemic peak, across subgroups. We also developed a dynamic deterministic model of HAV transmission among PEH/PWUD to estimate the basic reproduction number (R(0)), herd immunity threshold, V(c) and the effect of timing of the vaccination intervention on epidemic and economic outcomes. RESULTS: Of the 501 confirmed or probable cases, 385 (76.8%) were among PEH/PWUD. Among PEH/PWUD and within the general population, homelessness was a significant risk factor for infection in the initial stages of the outbreak (odds ratios for homeless versus not homeless: 2.62; 95% confidence interval (CI): 1.62-4.25 for PEH/PWUD and 2.39; 95% CI: 1.51-3.78 for all detected cases). Our estimate for R(0) ranges between 2.85 and 3.54, corresponding to an estimate of 69% (95% CI: 65-72) for herd immunity threshold and 76% (95% CI: 72%-80%) for V(c)(,) assuming a vaccine with 90% efficacy. The observed vaccination program was estimated to have averted 30 hospitalizations (95% CI: 19-43), associated with over US$490 000 (95% CI: $310 000-700 000) in hospitalization cost. Greater impact was observed with earlier and faster vaccination implementation. CONCLUSIONS: Vaccination coverage of at least 77% is likely required to prevent outbreaks of HAV among PEH/PWUD in Louisville, assuming a 90% vaccine efficacy. Proactive hepatitis A vaccination programs among PEH/PWUD will maximize health and economic benefits of these programs and reduce the likelihood of another outbreak.

BACKGROUND: Safe and effective hepatitis A vaccines have been recommended in the United States for at-risk adults since 1996; however, adult vaccination coverage is low. METHODS: Among a random sample of adult outbreak-associated hepatitis A cases from three states that were heavily affected by person-to-person hepatitis A outbreaks, we assessed the presence of documented Advisory Committee on Immunization Practices (ACIP) indications for hepatitis A vaccination, hepatitis A vaccination status, and whether cases that were epidemiologically linked to an outbreak-associated hepatitis A case had received postexposure prophylaxis (PEP). RESULTS: Overall, 74.1% of cases had a documented ACIP indication for hepatitis A vaccination. Fewer than 20% of epidemiologically linked cases received PEP. CONCLUSIONS: Efforts are needed to increase provider awareness of and adherence to ACIP childhood and adult hepatitis A vaccination and PEP recommendations in order to stop the current person-to-person hepatitis A outbreaks and prevent similar outbreaks in the future.

Traditional models of preventive care rely heavily on delivering services in established clinical settings. These settings might provide incomplete access for certain medically underserved populations, such as people who use drugs (PWUD), people experiencing homelessness (PEH), and people who are incarcerated or detained, because of either barriers in accessing care or past experiences of stigma and discrimination. Missed opportunities for delivering preventive vaccination services to medically underserved populations can lead to increased transmission, morbidity, and mortality. Between 2016 and 2021, widespread person-to-person outbreaks of hepatitis A across the United States—disproportionately affecting PWUD and PEH—highlighted both the challenges encountered and innovative solutions required in bringing preventive services to medically underserved populations. 1

BACKGROUND: To inform prevention strategies, we assessed the extent of SARS-CoV-2 transmission and settings in which transmission occurred in a Georgia public school district. METHODS: During December 1, 2020-January 22, 2021, SARS-CoV-2-infected index cases and their close contacts in schools were identified by school and public health officials. For in-school contacts, we assessed symptoms and offered SARS-CoV-2 RT-PCR testing; performed epidemiologic investigations and whole-genome sequencing to identify in-school transmission; and calculated secondary attack rate (SAR) by school setting (e.g., sports, elementary school classroom), index case role (i.e., staff, student), and index case symptomatic status. RESULTS: We identified 86 index cases and 1,119 contacts, 688 (63.1%) of whom received testing. Fifty-nine (8.7%) of 679 contacts tested positive; 15 (17.4%) of 86 index cases resulted in ≥2 positive contacts. Among 55 persons testing positive with available symptom data, 31 (56.4%) were asymptomatic. Highest SAR were in indoor, high-contact sports settings (23.8%, 95% confidence interval [CI] 12.7, 33.3), staff meetings/lunches (18.2%, CI 4.5-31.8), and elementary school classrooms (9.5%, CI 6.5-12.5). SAR was higher for staff (13.1%, CI 9.0-17.2) versus student index cases (5.8%, CI 3.6-8.0) and for symptomatic (10.9%, CI 8.1-13.9) versus asymptomatic index cases (3.0%, CI 1.0-5.5). CONCLUSIONS: Indoor sports may pose a risk to the safe operation of in-person learning. Preventing infection in staff members, through measures that include COVID-19 vaccination, is critical to reducing in-school transmission. Because many positive contacts were asymptomatic, contact tracing should be paired with testing, regardless of symptoms.

Drs Desai and Kim1 provided a brief overview of hepatitis A management. Their JAMA Insights article was timely considering the widespread person-to-person outbreaks of hepatitis A across the US since 2016.2 However, we note some discrepancies between this publication and the Advisory Committee on Immunization Practices (ACIP) recommendations that could affect the public health response to hepatitis A.3,4

OBJECTIVES: To assess trends and programmatic outcomes among infants born to hepatitis B surface antigen (HBsAg)-positive women from 2009 to 2017 and case-managed by the Centers for Disease Control and Prevention's national Perinatal Hepatitis B Prevention Program (PHBPP). METHODS: We analyzed 2009-2017 annual programmatic reports submitted by 56 US jurisdictions funded through the Centers for Disease Control and Prevention's PHBPP to assess characteristics of maternal-infant pairs and achievement of objectives of infant hepatitis B postexposure prophylaxis, vaccine series completion, and postvaccination serologic testing (PVST). We compared the number of maternal-infant pairs identified by the program with the number estimated born to HBsAg-positive women from 2009 to 2014 and 2015 to 2017 by using a race and/or ethnicity and maternal country of birth methodology, respectively. RESULTS: The PHBPP identified 103 825 infants born to HBsAg-positive women from 2009 to 2017, with a range of 10 956 to 12 103 infants annually. Births estimated annually to HBsAg-positive women increased nonsignificantly from 24 804 in 2009 to 26 444 in 2014 (P = .0540) and 20 678 in 2015 to 20 832 in 2017 (P = .8509). The proportion of infants identified annually increased overall from 48.1% to 52.6% (P = .0983). The proportion of case-managed infants receiving postexposure prophylaxis, at least 3 vaccine doses, and PVST increased overall from 94.7% to 97.0% (P = .0952), 83.1% to 84.7% (P = .5377) and 58.8% to 66.8% (P = .0002), respectively. CONCLUSIONS: The PHBPP has achieved success in managing infants born to HBsAg-positive women and ensuring their immunity to hepatitis B. Nonetheless, strategies are needed to close gaps between the number of infants estimated and identified, increase vaccine series completion, and increase ordering of recommended PVST for all case-managed infants.

BACKGROUND & AIMS: During 2016-2020, the United States experienced person-to-person hepatitis A outbreaks that are unprecedented in the vaccine era, during which case-fatality ratios reported by some jurisdictions exceeded those historically associated with hepatitis A. APPROACH & RESULTS: To identify factors associated with hepatitis A-related mortality, we performed a matched case-control study (matched on age [±5 years] and county of residence in a 1:4 ratio) using data collected from health department and hospital medical records of outbreak-associated patients in Kentucky, Michigan, and West Virginia. Controls were hepatitis A outbreak-associated patients who did not die. There were 110 cases (mean age 53.6 years) and 414 matched controls (mean age 51.9 years); most cases (68.2%) and controls (63.8%) were male. Significantly (p<0.05) higher odds of mortality were associated with pre-existing non-viral liver disease (adjusted odds ratio [aOR] 5.2), history of hepatitis B (aOR 2.4), diabetes (aOR 2.2), and cardiovascular disease (aOR 2.2), as well as initial MELD score ≥30 (aOR 10.0), AST/ALT ratio >2 (aOR 10.3), and platelet count <150,000/uL (aOR 3.7) among hepatitis A outbreak-associated patients in the independent multivariable conditional logistic regression analyses (each model adjusted for sex). CONCLUSIONS: Pre-existing liver disease, diabetes, cardiovascular disease, and initial MELD score ≥30, AST/ALT ratio ≥1, or platelet count <150,000/uL among hepatitis A patients were independently associated with higher odds of mortality. Providers should be vigilant for such features and have a low threshold to escalate care and consider consultation for liver transplantation. Our findings support the Advisory Committee on Immunization Practices recommendation to vaccinate persons with chronic liver disease, though future recommendations to include adults with diabetes and cardiovascular disease should be considered.

BACKGROUND: Since 2016, the US has experienced person-to-person hepatitis A outbreaks unprecedented in the vaccine era. The proportion of cases hospitalized in these outbreaks exceeds historical national surveillance data. METHODS: We described the epidemiology, characterized the reported increased morbidity, and identified factors associated with hospitalization during the outbreaks by reviewing a 10% random sample of outbreak-associated hepatitis A cases in Kentucky, Michigan, and West Virginia-three heavily affected states. We calculated descriptive statistics and conducted age-adjusted log-binomial regression analyses to identify factors associated with hospitalization. RESULTS: Participants in the random sample (n=817) were primarily male (62.5%) with mean age of 39.0 years; 51.8% were hospitalized. Among those with available information, 73.2% reported drug use, 14.0% were experiencing homelessness, 29.7% were currently or recently incarcerated, and 61.6% were epidemiologically linked to a known outbreak-associated case. Residence in Michigan (adjusted risk ratio [aRR] 1.8), being a man who has sex with men (aRR 1.5), non-injection drug use (aRR 1.3), and homelessness (aRR 1.3) were significantly (p<0.05) associated with hepatitis A-related hospitalization. CONCLUSIONS: Our findings support current Advisory Committee on Immunization Practices recommendations to vaccinate all persons who use drugs, men who have sex with men, and persons experiencing homelessness against hepatitis A.

BACKGROUND: In response to reported COVID-19 outbreaks among people experiencing homelessness (PEH) in other U.S. cities, we conducted multiple, proactive, facility-wide testing events for PEH living sheltered and unsheltered and homelessness service staff in Atlanta, Georgia. We describe SARS-CoV-2 prevalence and associated symptoms and review shelter infection prevention and control (IPC) policies. METHODS: PEH and staff were tested for SARS-CoV-2 by reverse transcription polymerase chain reaction (RT-PCR) during April 7-May 6, 2020. A subset of PEH and staff was screened for symptoms. Shelter assessments were conducted concurrently at a convenience sample of shelters using a standardized questionnaire. RESULTS: Overall, 2,875 individuals at 24 shelters and nine unsheltered outreach events underwent SARS-CoV-2 testing and 2,860 (99.5%) had conclusive test results. SARS-CoV-2 prevalence was 2.1% (36/1,684) among PEH living sheltered, 0.5% (3/628) among PEH living unsheltered, and 1.3% (7/548) among staff. Reporting fever, cough, or shortness of breath in the last week during symptom screening was 14% sensitive and 89% specific for identifying COVID-19 cases compared with RT-PCR. Prevalence by shelter ranged 0%-27.6%. Repeat testing 3-4 weeks later at four shelters documented decreased SARS-CoV-2 prevalence (0%-3.9%). Nine of 24 shelters completed shelter assessments and implemented IPC measures as part of the COVID-19 response. CONCLUSIONS: PEH living in shelters experienced higher SARS-CoV-2 prevalence compared with PEH living unsheltered. Facility-wide testing in congregate settings allowed for identification and isolation of COVID-19 cases and is an important strategy to interrupt SARS-CoV-2 transmission.

Hepatitis a is a vaccine-preventable, communicable disease of the liver caused by the hepatitis a virus (hav). The infection is transmitted via the fecal-oral route, usually from direct person-to-person contact or consumption of contaminated food or water. Hepatitis a is an acute, self-limited disease that does not result in chronic infection. Hav antibodies (immunoglobulin g [igg] anti-hav) produced in response to hav infection persist for life and protect against reinfection; igg anti-hav produced after vaccination confer long-term immunity. This report supplants and summarizes previously published recommendations from the advisory committee on immunization practices (acip) regarding the prevention of hav infection in the united states. Acip recommends routine vaccination of children aged 12-23 months and catch-up vaccination for children and adolescents aged 2-18 years who have not previously received hepatitis a (hepa) vaccine at any age. Acip recommends hepa vaccination for adults at risk for hav infection or severe disease from hav infection and for adults requesting protection against hav without acknowledgment of a risk factor. These recommendations also provide guidance for vaccination before travel, for postexposure prophylaxis, in settings providing services to adults, and during outbreaks.

The majority of paediatric Clostridioides difficile infections (CDI) are community-associated (CA), but few data exist regarding associated risk factors. We conducted a case-control study to evaluate CA-CDI risk factors in young children. Participants were enrolled from eight US sites during October 2014-February 2016. Case-patients were defined as children aged 1-5 years with a positive C. difficile specimen collected as an outpatient or 3 days of hospital admission, who had no healthcare facility admission in the prior 12 weeks and no history of CDI. Each case-patient was matched to one control. Caregivers were interviewed regarding relevant exposures. Multivariable conditional logistic regression was performed. Of 68 pairs, 44.1% were female. More case-patients than controls had a comorbidity (33.3% vs. 12.1%; P = 0.01); recent higher-risk outpatient exposures (34.9% vs. 17.7%; P = 0.03); recent antibiotic use (54.4% vs. 19.4%; P &lt; 0.0001); or recent exposure to a household member with diarrhoea (41.3% vs. 21.5%; P = 0.04). In multivariable analysis, antibiotic exposure in the preceding 12 weeks was significantly associated with CA-CDI (adjusted matched odds ratio, 6.25; 95% CI 2.18-17.96). Improved antibiotic prescribing might reduce CA-CDI in this population. Further evaluation of the potential role of outpatient healthcare and household exposures in C. difficile transmission is needed.

A Pseudomonas aeruginosa outbreak was investigated in a neonatal intensive care unit that had experienced a prior similar outbreak. The 8 cases identified included 2 deaths. An investigation found the cause of the outbreak: tap water from contaminated hospital plumbing which was used for humidifier reservoirs, neonatal bathing, and nutritional preparation. Our findings reinforce a recent Centers for Medicare & Medicaid Services memo recommending increased attention to water management to improve awareness, identification, mitigation, and prevention of water-associated, health care-associated infections.

Carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) express plasmid-encoded carbapenemases, enzymes that inactivate carbapenem antibiotics. They have the potential for epidemic spread through person-to-person transmission and horizontal transfer of resistance mechanisms (1,2). Typically, CP-CRE are associated with health care exposure. Clinical CRE infections can have mortality rates as high as 50% (3); however, the majority of CRE patients are asymptomatic. These asymptomatic colonized patients can serve as a source for transmission to other patients (4).