Use of an Additional Updated 2023-2024 COVID-19 Vaccine Dose for Adults Aged ≥65 Years: Recommendations of the Advisory Committee on Immunization Practices - United States, 2024.

COVID-19 remains an important public health threat, despite overall decreases in COVID-19-related severe disease since the start of the COVID-19 pandemic. COVID-19-associated hospitalization rates remain higher among adults aged ≥65 years relative to rates in younger adults, adolescents, and children; during October 2023-January 2024, 67% of all COVID-19-associated hospitalizations were among persons aged ≥65 years. On September 12, 2023, CDC's Advisory Committee on Immunization Practices (ACIP) recommended updated (2023-2024 Formula) COVID-19 vaccination with a monovalent XBB.1.5-derived vaccine for all persons aged ≥6 months to protect against severe COVID-19-associated illness and death. Because SARS-CoV-2 continues to circulate throughout the year, and because of the increased risk for COVID-19-related severe illness in persons aged ≥65 years, the protection afforded by updated vaccines against JN.1 and other currently circulating variants, and the expected waning of vaccine-conferred protection against disease, on February 28, 2024, ACIP recommended all persons aged ≥65 years receive 1 additional dose of the updated (2023-2024 Formula) COVID-19 vaccine. Implementation of these recommendations is expected to enhance immunity that might have waned and decrease the risk for severe COVID-19-associated outcomes, including death, among persons aged ≥65 years.

Interim Effectiveness of Updated 2023-2024 (Monovalent XBB.1.5) COVID-19 Vaccines Against COVID-19-Associated Hospitalization Among Adults Aged ≥18 Years with Immunocompromising Conditions - VISION Network, September 2023-February 2024.

In September 2023, CDC's Advisory Committee on Immunization Practices recommended updated 2023-2024 (monovalent XBB.1.5) COVID-19 vaccination for all persons aged ≥6 months to prevent COVID-19, including severe disease. As with past COVID-19 vaccines, additional doses may be considered for persons with immunocompromising conditions, who are at higher risk for severe COVID-19 and might have decreased response to vaccination. In this analysis, vaccine effectiveness (VE) of an updated COVID-19 vaccine dose against COVID-19-associated hospitalization was evaluated during September 2023-February 2024 using data from the VISION VE network. Among adults aged ≥18 years with immunocompromising conditions, VE against COVID-19-associated hospitalization was 38% in the 7-59 days after receipt of an updated vaccine dose and 34% in the 60-119 days after receipt of an updated dose. Few persons (18%) in this high-risk study population had received updated COVID-19 vaccine. All persons aged ≥6 months should receive updated 2023-2024 COVID-19 vaccination; persons with immunocompromising conditions may get additional updated COVID-19 vaccine doses ≥2 months after the last recommended COVID-19 vaccine.

Administration of the GSK Respiratory Syncytial Virus Vaccine to Pregnant Persons in Error.

The GSK and Pfizer respiratory syncytial virus (RSV) vaccines are both indicated for adults aged 60 years and older, but only the Pfizer product is approved for use in pregnancy to prevent RSV-associated lower respiratory tract disease in infants aged younger than 6 months. To assess for vaccine administration errors (ie, administration of the GSK RSV vaccine to pregnant persons) VAERS (Vaccine Adverse Event Reporting System), a U.S. passive reporting system, was searched for the time period from August 2023 to January 2024. A total of 113 reports of these administration errors were identified. Most reports (103, 91.2%) did not describe an adverse event. These administration errors are preventable with proper education and training and other preventive measures.

Early Estimates of Updated 2023-2024 (Monovalent XBB.1.5) COVID-19 Vaccine Effectiveness Against Symptomatic SARS-CoV-2 Infection Attributable to Co-Circulating Omicron Variants Among Immunocompetent Adults - Increasing Community Access to Testing Program, United States, September 2023-January 2024.

On September 12, 2023, CDC's Advisory Committee on Immunization Practices recommended updated 2023-2024 (updated) COVID-19 vaccination with a monovalent XBB.1.5-derived vaccine for all persons aged ≥6 months to prevent COVID-19, including severe disease. During fall 2023, XBB lineages co-circulated with JN.1, an Omicron BA.2.86 lineage that emerged in September 2023. These variants have amino acid substitutions that might increase escape from neutralizing antibodies. XBB lineages predominated through December 2023, when JN.1 became predominant in the United States. Reduction or failure of spike gene (S-gene) amplification (i.e., S-gene target failure [SGTF]) in real-time reverse transcription-polymerase chain reaction testing is a time-dependent, proxy indicator of JN.1 infection. Data from the Increasing Community Access to Testing SARS-CoV-2 pharmacy testing program were analyzed to estimate updated COVID-19 vaccine effectiveness (VE) (i.e., receipt versus no receipt of updated vaccination) against symptomatic SARS-CoV-2 infection, including by SGTF result. Among 9,222 total eligible tests, overall VE among adults aged ≥18 years was 54% (95% CI = 46%-60%) at a median of 52 days after vaccination. Among 2,199 tests performed at a laboratory with SGTF testing, VE 60-119 days after vaccination was 49% (95% CI = 19%-68%) among tests exhibiting SGTF and 60% (95% CI = 35%-75%) among tests without SGTF. Updated COVID-19 vaccines provide protection against symptomatic infection, including against currently circulating lineages. CDC will continue monitoring VE, including for expected waning and against severe disease. All persons aged ≥6 months should receive an updated COVID-19 vaccine dose.

Effectiveness of a bivalent mRNA vaccine dose against symptomatic SARS-CoV-2 infection among U.S. Healthcare personnel, September 2022-May 2023.

BACKGROUND: Bivalent mRNA vaccines were recommended since September 2022. However, coverage with a recent vaccine dose has been limited, and there are few robust estimates of bivalent VE against symptomatic SARS-CoV-2 infection (COVID-19). We estimated VE of a bivalent mRNA vaccine dose against COVID-19 among eligible U.S. healthcare personnel who had previously received monovalent mRNA vaccine doses. METHODS: We conducted a case-control study in 22 U.S. states, and enrolled healthcare personnel with COVID-19 (case-participants) or without COVID-19 (control-participants) during September 2022-May 2023. Participants were considered eligible for a bivalent mRNA dose if they had received 2-4 monovalent (ancestral-strain) mRNA vaccine doses, and were ≥67 days after the most recent vaccine dose. We estimated VE of a bivalent mRNA dose using conditional logistic regression, accounting for matching by region and four-week calendar period. We adjusted estimates for age group, sex, race and ethnicity, educational level, underlying health conditions, community COVID-19 exposure, prior SARS-CoV-2 infection, and days since the last monovalent mRNA dose. RESULTS: Among 3,647 healthcare personnel, 1,528 were included as case-participants and 2,119 as control-participants. Participants received their last monovalent mRNA dose a median of 404 days previously; 1,234 (33.8%) also received a bivalent mRNA dose a median of 93 days previously. Overall, VE of a bivalent dose was 34.1% (95% CI, 22.6%-43.9%) against COVID-19 and was similar by product, days since last monovalent dose, number of prior doses, age group, and presence of underlying health conditions. However, VE declined from 54.8% (95% CI, 40.7%-65.6%) after 7-59 days to 21.6% (95% CI 5.6%-34.9%) after ≥60 days. CONCLUSIONS: Bivalent mRNA COVID-19 vaccines initially conferred approximately 55% protection against COVID-19 among U.S. healthcare personnel. However, protection waned after two months. These findings indicate moderate initial protection against symptomatic SARS-CoV-2 infection by remaining up-to-date with COVID-19 vaccines.

Characteristics and Clinical Outcomes of Vaccine-Eligible US Children Under-5 Years Hospitalized for Acute COVID-19 in a National Network.

BACKGROUND AND OBJECTIVES: In June 2022, the mRNA COVID-19 vaccination was recommended for young children. We examined clinical characteristics and factors associated with vaccination status among vaccine-eligible young children hospitalized for acute COVID-19. METHODS: We enrolled inpatients 8 months to <5 years of age with acute community-acquired COVID-19 across 28 US pediatric hospitals from September 20, 2022 to May 31, 2023. We assessed demographic and clinical factors, including the highest level of respiratory support, and vaccination status defined as unvaccinated, incomplete, or complete primary series [at least 2 (Moderna) or 3 (Pfizer-BioNTech) mRNA vaccine doses ≥14 days before hospitalization]. RESULTS: Among 597 children, 174 (29.1%) patients were admitted to the intensive care unit and 75 (12.6%) had a life-threatening illness, including 51 (8.5%) requiring invasive mechanical ventilation. Children with underlying respiratory and neurologic/neuromuscular conditions more frequently received higher respiratory support. Only 4.5% of children hospitalized for COVID-19 (n = 27) had completed their primary COVID-19 vaccination series and 7.0% (n = 42) of children initiated but did not complete their primary series. Among 528 unvaccinated children, nearly half (n = 251) were previously healthy, 3 of them required extracorporeal membrane oxygenation for acute COVID-19 and 1 died. CONCLUSIONS: Most young children hospitalized for acute COVID-19, including most children admitted to the intensive care unit and with life-threatening illness, had not initiated COVID-19 vaccination despite being eligible. Nearly half of these children had no underlying conditions. Of the small percentage of children who initiated a COVID-19 primary series, most had not completed it before hospitalization.

Development of COVID-19 vaccine policy - United States, 2020-2023.

COVID-19 vaccines represent a great scientific and public health achievement in the face of overwhelming pressures from a global pandemic, preventing millions of hospitalizations and deaths due to COVID-19 vaccines in the United States. Over 675 million doses of COVID-19 vaccines have been administered in the United States, and over 80% of the U.S. population has had at least 1 dose of a COVID-19 vaccine. Over the course of the COVID-19 pandemic in the United States, over one million people died from COVID-19, and over six million were hospitalized. It has been estimated that COVID-19 vaccines prevented more than 18 million additional hospitalizations and more than 3 million additional deaths due to COVID-19 in the United States. From the beginning of the COVID-19 pandemic in 2020 through June 2023, ACIP had 35 COVID-19 focused meetings and 24 votes for COVID-19 vaccine recommendations. ACIP had the critical task of rapidly and thoroughly reviewing emerging and evolving data on COVID-19 epidemiology and vaccines, as well as making comprehensive population-based recommendations for vaccine policy and considerations for implementation through a transparent and evidence-based framework. Safe and effective COVID-19 vaccines, recommended through transparent policy discussions with ACIP, remain the best tool we have to prevent serious illness, hospitalization and death from COVID-19.

Building the U.S. COVID-19 vaccine effectiveness program: Past successes and future directions.

COVID-19 vaccines were originally authorized in the United States in December 2020 on the basis of safety, immunogenicity, and clinical efficacy data from randomized controlled trials (RCTs). However, real-world vaccine effectiveness (VE) data are necessary to provide information on how the vaccines work in populations not included in the RCTs (e.g., nursing home residents), against new SARS-CoV-2 variants, with increasing time since vaccination, and in populations with increasing levels of prior infection. The goal of CDC's COVID-19 VE program is to provide timely and robust data to support ongoing policy decisions and implementation of vaccination and includes VE platforms to study the spectrum of illness, from infection to critical illness. Challenges to estimating VE include accurate ascertainment of vaccination history, outcome status, changing rates of prior infection, emergence of new variants, and appropriate interpretation of absolute and relative VE measures. CDC COVID-19 VE platforms have played a pivotal role in numerous vaccine policy decisions since 2021 and will continue to play a key role in future decisions as the vaccine program moves from an emergency response to a routine schedule.

Use of Updated COVID-19 Vaccines 2023-2024 Formula for Persons Aged ≥6 Months: Recommendations of the Advisory Committee on Immunization Practices - United States, September 2023.

COVID-19 vaccines protect against severe COVID-19-associated outcomes, including hospitalization and death. As SARS-CoV-2 has evolved, and waning vaccine effectiveness has been noted, vaccine formulations and policies have been updated to provide continued protection against severe illness and death from COVID-19. Since September 2022, bivalent mRNA COVID-19 vaccines have been recommended in the United States, but the variants these vaccines protect against are no longer circulating widely. On September 11, 2023, the Food and Drug Administration (FDA) approved the updated (2023-2024 Formula) COVID-19 mRNA vaccines by Moderna and Pfizer-BioNTech for persons aged ≥12 years and authorized these vaccines for persons aged 6 months-11 years under Emergency Use Authorization (EUA). On October 3, 2023, FDA authorized the updated COVID-19 vaccine by Novavax for use in persons aged ≥12 years under EUA. The updated COVID-19 vaccines include a monovalent XBB.1.5 component, which is meant to broaden vaccine-induced immunity and provide protection against currently circulating SARS-CoV-2 XBB-sublineage variants including against severe COVID-19-associated illness and death. On September 12, 2023, the Advisory Committee on Immunization Practices recommended vaccination with updated COVID-19 vaccines for all persons aged ≥6 months. These recommendations will be reviewed as new evidence becomes available or new vaccines are approved and might be updated.

Effectiveness of Maternal mRNA COVID-19 Vaccination During Pregnancy Against COVID-19-Associated Hospitalizations in Infants Aged <6 Months During SARS-CoV-2 Omicron Predominance - 20 States, March 9, 2022-May 31, 2023.

Infants aged <6 months are not eligible for COVID-19 vaccination. Vaccination during pregnancy has been associated with protection against infant COVID-19-related hospitalization. The Overcoming COVID-19 Network conducted a case-control study during March 9, 2022-May 31, 2023, to evaluate the effectiveness of maternal receipt of a COVID-19 vaccine dose (vaccine effectiveness [VE]) during pregnancy against COVID-19-related hospitalization in infants aged <6 months and a subset of infants aged <3 months. VE was calculated as (1 - adjusted odds ratio) x 100% among all infants aged <6 months and <3 months. Case-patients (infants hospitalized for COVID-19 outside of birth hospitalization and who had a positive SARS-CoV-2 test result) and control patients (infants hospitalized for COVID-19-like illness with a negative SARS-CoV-2 test result) were compared. Odds ratios were determined using multivariable logistic regression, comparing the odds of receipt of a maternal COVID-19 vaccine dose (completion of a 2-dose vaccination series or a third or higher dose) during pregnancy with maternal nonvaccination between case- and control patients. VE of maternal vaccination during pregnancy against COVID-19-related hospitalization was 35% (95% CI = 15%-51%) among infants aged <6 months and 54% (95% CI = 32%-68%) among infants aged <3 months. Intensive care unit admissions occurred in 23% of all case-patients, and invasive mechanical ventilation was more common among infants of unvaccinated (9%) compared with vaccinated mothers (1%) (p = 0.02). Maternal vaccination during pregnancy provides some protection against COVID-19-related hospitalizations among infants, particularly those aged <3 months. Expectant mothers should remain current with COVID-19 vaccination to protect themselves and their infants from hospitalization and severe outcomes associated with COVID-19.

Use of the Pfizer Respiratory Syncytial Virus Vaccine During Pregnancy for the Prevention of Respiratory Syncytial Virus-Associated Lower Respiratory Tract Disease in Infants: Recommendations of the Advisory Committee on Immunization Practices - United States, 2023.

Respiratory syncytial virus (RSV) is the leading cause of hospitalization among U.S. infants. Nirsevimab (Bevfortus, Sanofi and AstraZeneca) is recommended to prevent RSV-associated lower respiratory tract infection (LRTI) in infants. In August 2023, the Food and Drug Administration (FDA) approved RSVpreF vaccine (Abrysvo, Pfizer Inc.) for pregnant persons as a single dose during 32-36 completed gestational weeks (i.e., 32 weeks and zero days' through 36 weeks and 6 days' gestation) to prevent RSV-associated lower respiratory tract disease in infants aged <6 months. Since October 2021, CDC's Advisory Committee on Immunization Practices (ACIP) RSV Vaccines Pediatric/Maternal Work Group has reviewed RSV epidemiology and evidence regarding safety, efficacy, and potential economic impact of pediatric and maternal RSV prevention products, including RSVpreF vaccine. On September 22, 2023, ACIP and CDC recommended RSVpreF vaccine using seasonal administration (i.e., during September through end of January in most of the continental United States) for pregnant persons as a one-time dose at 32-36 weeks' gestation for prevention of RSV-associated LRTI in infants aged <6 months. Either maternal RSVpreF vaccination during pregnancy or nirsevimab administration to the infant is recommended to prevent RSV-associated LRTI among infants, but both are not needed for most infants. All infants should be protected against RSV-associated LRTI through use of one of these products.

Effectiveness of a Messenger RNA Vaccine Booster Dose Against Coronavirus Disease 2019 Among US Healthcare Personnel, October 2021-July 2022.

Background: Protection against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (coronavirus disease 2019 [COVID-19]) can limit transmission and the risk of post-COVID conditions, and is particularly important among healthcare personnel. However, lower vaccine effectiveness (VE) has been reported since predominance of the Omicron SARS-CoV-2 variant. Methods: We evaluated the VE of a monovalent messenger RNA (mRNA) booster dose against COVID-19 from October 2021 to June 2022 among US healthcare personnel. After matching case-participants with COVID-19 to control-participants by 2-week period and site, we used conditional logistic regression to estimate the VE of a booster dose compared with completing only 2 mRNA doses >150 days previously, adjusted for multiple covariates. Results: Among 3279 case-participants and 3998 control-participants who had completed 2 mRNA doses, we estimated that the VE of a booster dose against COVID-19 declined from 86% (95% confidence interval, 81%-90%) during Delta predominance to 65% (58%-70%) during Omicron predominance. During Omicron predominance, VE declined from 73% (95% confidence interval, 67%-79%) 14-60 days after the booster dose, to 32% (4%-52%) ≥120 days after a booster dose. We found that VE was similar by age group, presence of underlying health conditions, and pregnancy status on the test date, as well as among immunocompromised participants. Conclusions: A booster dose conferred substantial protection against COVID-19 among healthcare personnel. However, VE was lower during Omicron predominance, and waning effectiveness was observed 4 months after booster dose receipt during this period. Our findings support recommendations to stay up to date on recommended doses of COVID-19 vaccines for all those eligible.

Effectiveness of Monovalent and Bivalent mRNA Vaccines in Preventing COVID-19-Associated Emergency Department and Urgent Care Encounters Among Children Aged 6 Months-5 Years - VISION Network, United States, July 2022-June 2023.

On June 19, 2022, the original monovalent mRNA COVID-19 vaccines were approved as a primary series for children aged 6 months-4 years (Pfizer-BioNTech) and 6 months-5 years (Moderna) based on safety, immunobridging, and limited efficacy data from clinical trials. On December 9, 2022, CDC expanded recommendations for use of updated bivalent vaccines to children aged ≥6 months. mRNA COVID-19 vaccine effectiveness (VE) against emergency department or urgent care (ED/UC) encounters was evaluated within the VISION Network during July 4, 2022-June 17, 2023, among children with COVID-19-like illness aged 6 months-5 years. Among children aged 6 months-5 years who received molecular SARS-CoV-2 testing during August 1, 2022-June 17, 2023, VE of 2 monovalent Moderna doses against ED/UC encounters was 29% (95% CI = 12%-42%) ≥14 days after dose 2 (median = 100 days after dose 2; IQR = 63-155 days). Among children aged 6 months-4 years with a COVID-19-like illness who received molecular testing during September 19, 2022-June 17, 2023, VE of 3 monovalent Pfizer-BioNTech doses was 43% (95% CI = 17%-61%) ≥14 days after dose 3 (median = 75 days after dose 3; IQR = 40-139 days). Effectiveness of ≥1 bivalent dose, comparing children with at least a complete primary series and ≥1 bivalent dose to unvaccinated children, irrespective of vaccine manufacturer, was 80% (95% CI = 42%-96%) among children aged 6 months-5 years a median of 58 days (IQR = 32-83 days) after the dose. All children should stay up to date with recommended COVID-19 vaccines, including initiation of COVID-19 vaccination immediately when they are eligible.

Use of Nirsevimab for the Prevention of Respiratory Syncytial Virus Disease Among Infants and Young Children: Recommendations of the Advisory Committee on Immunization Practices - United States, 2023.

Respiratory syncytial virus (RSV) is the leading cause of hospitalization among U.S. infants. In July 2023, the Food and Drug Administration approved nirsevimab, a long-acting monoclonal antibody, for passive immunization to prevent RSV-associated lower respiratory tract infection among infants and young children. Since October 2021, the Advisory Committee on Immunization Practices (ACIP) Maternal and Pediatric RSV Work Group has reviewed evidence on the safety and efficacy of nirsevimab among infants and young children. On August 3, 2023, ACIP recommended nirsevimab for all infants aged <8 months who are born during or entering their first RSV season and for infants and children aged 8-19 months who are at increased risk for severe RSV disease and are entering their second RSV season. On the basis of pre-COVID-19 pandemic patterns, nirsevimab could be administered in most of the continental United States from October through the end of March. Nirsevimab can prevent severe RSV disease among infants and young children at increased risk for severe RSV disease.

Interim Recommendations for Use of Bivalent mRNA COVID-19 Vaccines for Persons Aged ≥6 Months - United States, April 2023.

Throughout the national public health emergency declared in response to the COVID-19 pandemic, CDC, guided by the Advisory Committee on Immunization Practices (ACIP), has offered evidence-based recommendations for the use of COVID-19 vaccines in U.S. populations after each regulatory action by the Food and Drug Administration (FDA). During August 2022-April 2023, FDA amended its Emergency Use Authorizations (EUAs) to authorize the use of a single, age-appropriate, bivalent COVID-19 vaccine dose (i.e., containing components from the ancestral and Omicron BA.4/BA.5 strains in equal amounts) for all persons aged ≥6 years, use of bivalent COVID-19 vaccine doses for children aged 6 months-5 years, and additional bivalent doses for immunocompromised persons and adults aged ≥65 years (1). ACIP voted in September 2022 on the use of the bivalent vaccine, and CDC made recommendations after the September vote and subsequently, through April 2023, with input from ACIP. This transition to a single bivalent COVID-19 vaccine dose for most persons, with additional doses for persons at increased risk for severe disease, facilitates implementation of simpler, more flexible recommendations. Three COVID-19 vaccines are currently available for use in the United States and recommended by ACIP: 1) the bivalent mRNA Pfizer-BioNTech COVID-19 vaccine, 2) the bivalent mRNA Moderna COVID-19 vaccine, and 3) the monovalent adjuvanted, protein subunit-based Novavax COVID-19 vaccine.* As of August 31, 2022, monovalent mRNA vaccines based on the ancestral SARS-CoV-2 strain are no longer authorized for use in the United States (1).

Safety and Effectiveness of Maternal COVID-19 Vaccines Among Pregnant People and Infants.

Evidence has consistently demonstrated that COVID-19 messenger RNA (mRNA) vaccines are safe when given during pregnancy. COVID-19 mRNA vaccines protect pregnant people and their infants who are too young to receive COVID-19 vaccines. Although generally protective, monovalent vaccine effectiveness was lower during SARS-CoV-2 Omicron variant predominance, in part due to changes in the Omicron spike protein. Bivalent vaccines, that combine ancestral strain and Omicron variant, may improve protection against Omicron variants. Everyone, including pregnant people, should stay up to date with recommended COVID-19 vaccines and bivalent booster, when eligible.

Effectiveness of Booster Doses of Monovalent mRNA COVID-19 Vaccine Against Symptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Children, Adolescents, and Adults During Omicron Subvariant BA.2/BA.2.12.1 and BA.4/BA.5 Predominant Periods.

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) BA.2/BA.2.12.1 and BA.4/BA.5 subvariants have mutations associated with increased capacity to evade immunity when compared with prior variants. We evaluated mRNA monovalent booster dose effectiveness among persons ≥5 years old during BA.2/BA.2.12.1 and BA.4/BA.5 predominance. Methods: A test-negative, case-control analysis included data from 12 148 pharmacy SARS-CoV-2 testing sites nationwide for persons aged ≥5 years with ≥1 coronavirus disease-2019 (COVID-19)-like symptoms and a SARS-CoV-2 nucleic acid amplification test from April 2 to August 31, 2022. Relative vaccine effectiveness (rVE) was estimated comparing 3 doses of COVID-19 mRNA monovalent vaccine to 2 doses; for tests among persons ≥50 years, rVE estimates also compared 4 doses to 3 doses (≥4 months since third dose). Results: A total of 760 986 test-positive cases and 817 876 test-negative controls were included. Among individuals ≥12 years, rVE of 3 versus 2 doses ranged by age group from 45% to 74% at 1-month post vaccination and waned to 0% by 5-7 months post vaccination during the BA.4/BA.5 period.Adults aged ≥50 years (fourth dose eligible) who received 4 doses were less likely to have symptomatic SARS-CoV-2 infection compared with those with 3 doses; this rVE remained >0% through at least 3 months since last dose. For those aged ≥65 years, rVE of 4 versus 3 doses 1-month post vaccination was higher during BA.2/BA.2.12.1 (rVE = 49%; 95% confidence interval [CI], 43%-53%) than BA.4/BA.5 (rVE = 40%; 95% CI, 36%-44%). In 50- to 64-year-olds, rVE estimates were similar. Conclusions: Monovalent mRNA booster doses provided additional protection against symptomatic SARS-CoV-2 infection during BA.2/BA.2.12.1 and BA.4/BA.5 subvariant circulation, but protection waned over time.

Effectiveness of BNT162b2 COVID-19 Vaccination in Children and Adolescents.

OBJECTIVES: We assessed BNT162b2 vaccine effectiveness (VE) against mild to moderate and severe coronavirus disease 2019 (COVID-19) in children and adolescents through the Omicron BA.4/BA.5 period. METHODS: Using VISION Network records from April 2021 to September 2022, we conducted a test-negative, case-control study assessing VE against COVID-19-associated emergency department/urgent care (ED/UC) encounters and hospitalizations using logistic regression, conditioned on month and site, adjusted for covariates. RESULTS: We compared 9800 ED/UC cases with 70 232 controls, and 305 hospitalized cases with 2612 controls. During Delta, 2-dose VE against ED/UC encounters at 12 to 15 years was initially 93% (95% confidence interval 89 to 95), waning to 77% (69% to 84%) after ≥150 days. At ages 16 to 17, VE was initially 93% (86% to 97%), waning to 72% (63% to 79%) after ≥150 days. During Omicron, VE at ages 12 to 15 was initially 64% (44% to 77%), waning to 13% (3% to 23%) after ≥150 days; at ages 16 to 17 VE was 31% (10% to 47%) during days 60 to 149, waning to 7% (-8 to 20%) after 150 days. A monovalent booster increased VE to 54% (40% to 65%) at ages 12 to 15 and 46% (30% to 58%) at ages 16 to 17. At ages 5 to 11, 2-dose VE was 49% (33% to 61%) initially and 41% (29% to 51%) after 150 days. During Delta, VE against hospitalizations at ages 12 to 17 was high (>97%), and at ages 16 to 17 remained 98% (73% to 100%) beyond 150 days; during Omicron, hospitalizations were too infrequent to precisely estimate VE. CONCLUSIONS: BNT162b2 protected children and adolescents against mild to moderate and severe COVID-19. VE was lower during Omicron predominance including BA.4/BA.5, waned after dose 2 but increased after a monovalent booster. Children and adolescents should receive all recommended COVID-19 vaccinations.

Comparison of outpatient antibiotic prescriptions among older adults in IQVIA Xponent and publicly available Medicare Part D data, 2018.

The distributions of antibiotic prescriptions by geography, antibiotic class, and prescriber specialty are similar in the US Centers for Medicare and Medicaid Services (CMS) Part D Prescriber Public Use Files and IQVIA Xponent dataset. Public health organizations and healthcare systems can use these data to track antibiotic use and guide antibiotic stewardship interventions for older adults.