omicron hospitalization rate vaccinated by age

Receipt of one dose especially during the third trimester was also associated with a reduced risk of infants testing positive for SARS-CoV-2 during the first 6 months of life during the Delta dominant period. Most mothers (1032 of 1138) who received only one dose received the vaccine during the third trimester. Morb. China informed the WHO about the case, which involves a 53-year-old woman, on Feb 24. 1CDC COVID-19 Emergency Response Team; 2General Dynamics Information Technology, Atlanta, Georgia; 3California Emerging Infections Program, Oakland, California; 4Career Epidemiology Field Officer Program, CDC; 5Colorado Department of Public Health & Environment; 6Connecticut Emerging Infections Program, Yale School of Public Health, New Haven, Connecticut; 7Emory University School of Medicine, Atlanta, Georgia; 8Georgia Emerging Infections Program, Georgia Department of Public Health; 9Atlanta Veterans Affairs Medical Center, Atlanta, Georgia; 10Iowa Department of Public Health; 11Michigan Department of Health and Human Services; 12Minnesota Department of Health; 13New Mexico Emerging Infections Program, University of New Mexico, Albuquerque, New Mexico; 14New York State Department of Health; 15University of Rochester School of Medicine and Dentistry, Rochester, New York; 16Ohio Department of Health; 17Public Health Division, Oregon Health Authority; 18Vanderbilt University Medical Center, Nashville, Tennessee; 19Utah Department of Health. References to non-CDC sites on the Internet are Vaccination status is not available for Iowa and cases from Iowa are excluded from analyses that examined vaccination status. These cookies may also be used for advertising purposes by these third parties. New charts from the Centers for Disease Control and Prevention (CDC) showed that hospitalization rates were much lower among those who were vaccinated even as Omicron was sweeping the nation. 45 C.F.R. Association of COVID-19 vaccination during pregnancy with incidence of SARS-CoV-2 infection in infants. During the period of Omicron predominance, hospitalization rates increased most sharply among Black adults in the United States relative to all other racial and ethnic groups examined and reached the highest rate observed among all racial and ethnic groups since the beginning of the pandemic. Foppa, I. M., Haber, M., Ferdinands, J. M. & Shay, D. K. The case test-negative design for studies of the effectiveness of influenza vaccine. The results were published yesterday in JAMA Network Open. Implementing strategies that result in the equitable receipt of COVID-19 vaccinations, through building vaccine confidence, raising awareness of the benefits of vaccination, and removing barriers to vaccination access among persons with disproportionately higher hospitalizations rates from COVID-19, including Black adults, is an urgent public health priority. Klein, N. P. et al. With the emergence of the SARS-CoV-2 Omicron variant in late 2021, Canadian public health case/contact testing was scaled back due to high infection rates with milder symptoms in a highly vaccinated population. Adults whose vaccination status had not yet been verified using the immunization information system data were considered to have unknown vaccination status and were included in total proportions but not stratified by vaccination status. To account for the correlation between infants with the same mother, we fit marginal Cox proportional hazards models using robust sandwich variance estimates. If the SARS-CoV-2 test date was not available, hospital admission date was used. This is in keeping with the age profile. https://doi.org/10.1038/s41467-023-36547-4, DOI: https://doi.org/10.1038/s41467-023-36547-4. pdf files, Omicron: fewer adverse outcomes come with new dangers, Statement on offensive historical content, Redistribute or republish the final article, Reuse portions or extracts from the article in other works. TN, NMF, SGN, DDA, AMP, and ST wrote the original draft of the manuscript. In supplemental analyses by trimester of vaccination, receipt of the second dose during the second and third trimesters reduced the risk of infants testing SARS-CoV-2 positive during the Delta dominant period by 91% (95% CI: 63, 98) and 85% (95% CI: 50, 96), respectively, during the first 2 months of life, by 59% (95% CI: 21, 79) and 67% (95% CI: 37, 83) during the first 4 months of life and by 64% (95% CI:31, 81) and 53% (95% CI: 24, 71) during the first 6 months of life. Weekly rates among unvaccinated adults and adults who received a primary COVID-19 vaccination series with a booster or additional dose peaked at 149.8 (January 8, 2022) and 11.7 (January 22, 2022), respectively. and/or the original MMWR paper copy for printable versions of official text, figures, and tables. volume14, Articlenumber:894 (2023) Risk was especially high for people with severe combined immunodeficiency (HR, 6.2). 26K views, 1.2K likes, 65 loves, 454 comments, 23 shares, Facebook Watch Videos from Citizen TV Kenya: #FridayNight SARS-CoV-2 variant data update, England: Version 21. Data about boosters was only available for those over 50. Thus, this design better adjusts for healthcare-seeking behavior31,32, but it may also introduce other biases including selection bias33. Severe cases may increase in the wake of holiday parties where people of all ages mixed. Safety and efficacy of single-dose Ad26.COV2.S vaccine against Covid-19. Google Scholar. J. Med. JAMA 326, 16291631 (2021). From this cohort, the study excluded the following infants born to (1) mothers who were not between ages 16 and 50 years at pregnancy onset; (2) mothers who did not have a primary KPNC facility assignment; (3) mothers who were not continuous KPNC members from December 15, 2020 until delivery; (4) mothers who had a positive nasal/throat swab for SARS-CoV-2 by polymerase chain reaction (PCR) prior to pregnancy onset; (5) mothers who had a positive SARS-CoV-2 antibody test documented by KPNC prior to the onset of pregnancy; (6) mothers who received one or more doses of COVID-19 vaccine prior to pregnancy onset. JAMA Intern. 3501 et seq. Pediatr. Voysey, M., Pollard, A. J., Sadarangani, M. & Fanshawe, T. R. Prevalence and decay of maternal pneumococcal and meningococcal antibodies: a meta-analysis of type-specific decay rates. image, https://doi.org/10.1038/s41586-022-04474-x, https://doi.org/10.1038/s41586-022-04479-6, https://doi.org/10.1101/2022.01.18.22269082, https://www.gov.uk/government/statistics/national-flu-and-covid-19-surveillance-reports-2021-to-2022-season, Download .pdf (.95 MMWR and Morbidity and Mortality Weekly Report are service marks of the U.S. Department of Health and Human Services. Get the most important science stories of the day, free in your inbox. All authors (O.Z., B.F., N.P.K., T.R., M.G., E.L., P.R., K.G., S.O., and E.L.) critically reviewed the manuscript and decided to proceed with publication. Age was the most important risk factor for COVID-19 death (eg, HR, 31.3 for an 80-year-old vs a 50-year-old). We also conducted analyses based on the trimester during which the vaccine was received during pregnancy (first, second, or third trimester). IMV status was missing in 1.4% (weighted) of hospitalizations; these hospitalizations are otherwise included elsewhere in the analysis. The TND analyses avoid this bias by limiting the analysis to infants who were tested for SARS-CoV-2. These data should be taken with a grain of salt. This case-positive, control-test-negative design also referred to as the test-negative design (TND) has often been used in studies of vaccine effectiveness. CAS B, Severe outcomes included hospitalization and death. Morb. adjudicated chart reviews. Protection during both periods decreased as infants aged from 2 months to 6 months. Zerbo, O., Ray, G.T., Fireman, B. et al. This was the highest age-adjusted weekly rate observed among any racial and ethnic group during the pandemic. PubMed Central O.Z., N.P.K., and B.F. conceived and designed the study. Cohen-Stavi, C. J. et al. A and B, Markers indicate estimates, with vertical lines indicating 95% CIs. From Jan 1 to Mar 16, 2022, when Omicron was predominant, 4,781 (0.02%) of 19,473,570 booster recipients died of COVID-19, and 58,020 (0.3%) died of other causes. MMWR Morb Mortal Wkly Rep 2022;71:14652. What are the implications for public health practice? It's not clear which variant might have been associated with these hospitalizations. * Data are from a weighted sample of hospitalized nonpregnant adults with completed medical record abstractions and a discharge disposition. Infect. "The high hospitalization rates in unvaccinated compared with vaccinated persons with and without a booster dose underscores the importance of COVID-19 vaccinations in preventing hospitalizations and suggests that increasing vaccination coverage, including booster dose coverage, can prevent hospitalizations, serious illness, and death," the researchers wrote. Initial hospital data from England and Denmark also suggest Omicron cases are less severe. Proportions between the pre-Delta and Delta period were compared using chi-square tests; p-values <0.05 were considered statistically significant, adjusted for multiple comparisons using the Bonferroni correction method. Nat Commun 14, 894 (2023). Kim, L. et al. Infants were followed from birth until the first positive SARS-CoV-2 test by PCR at age 2, 4, or 6 months, with censoring due to death, health plan disenrollment, or end of follow-up (May 31, 2022). During the Omicron dominant period, receipt of 2 doses during pregnancy reduced the risk of the infant testing SARS-CoV-2 positive by 21% (95% CI: 21, 48) during the first 2 months of life, 14% (95% CI: 8, 32) during the first 4 months of life, and 13% (95% CI: 3, 26) during the first 6 months of life (Table2). Adults who received booster doses were classified as those who completed their primary vaccination series and received an additional or booster dose of vaccine on or after August 13, 2021, at any time after the completion of their primary series, and 14 days before a positive test result for SARS-CoV-2, because COVID-19associated hospitalizations are a lagging indicator, and time passed after receipt of a booster dose has been shown to be associated with reduced rates of COVID-19 infection (https://www.nejm.org/doi/full/10.1056/NEJMoa2114255). J., Fireman. Percentages presented were weighted to account for the probability of selection for sampled cases (3). Relative to the Delta-predominant period, a larger proportion of hospitalized Black adults were unvaccinated. Mortal. Weekly COVID-19-associated hospitalization rates among U.S. infants and children aged 0-4 years have declined since the peak of January 8, 2022; however, peak rates during Omicron predominance were approximately five times those of the peak during Delta predominance. Razzaghi, H. et al. COVID-19 hospitalization rates per 100,000 population by age and vaccination status, January 05 to February 01, 2023 Age group Age-specific rate per 100,000 among unvaccinated individuals Age-specific rate per 100,000 among those who received at least one booster dose Likelihood of unvaccinated individuals being hospitalized with ; COVID-NET Surveillance Team. Hospitalization rates were 10.5 times higher in the unvaccinated and 2.5 times higher in vaccinated patients with no booster than in booster recipients. Article Provided by the Springer Nature SharedIt content-sharing initiative. Morb. Preliminary findings of mRNA Covid-19 vaccine safety in pregnant persons. However, vaccination during pregnancy was less effective at protecting infants against SARS-CoV-2 infection during the Omicron period. Data among adults over 50 showed that a booster shot gave even stronger protection. Age-adjusted rates were calculated by dividing the number of hospitalized COVID-19 patients by population estimates for race/ethnicity, and vaccination status in the catchment area. Saving Lives, Protecting People, https://covid.cdc.gov/covid-data-tracker/#variant-proportions, https://www.cdc.gov/coronavirus/2019-ncov/covid-data/covid-net/purpose-methods.html, https://www.cdc.gov/mmwr/volumes/69/wr/mm6915e3.htm, https://www.cdc.gov/nchs/nvss/bridged_race.htm, https://www.medrxiv.org/content/10.1101/2021.08.27.21262356v1, https://www.cdc.gov/mmwr/volumes/70/wr/mm7050e2.htm, https://www.nejm.org/doi/full/10.1056/NEJMoa2114255, https://medrxiv.org/cgi/content/short/2021.08.27.21262356v1, https://www.medrxiv.org/content/10.1101/2022.01.11.22269045v1, https://data.cdc.gov/Vaccinations/COVID-19-Vaccination-Demographics-in-the-United-St/km4m-vcsb, https://www.cdc.gov/coronavirus/2019-ncov/vaccines/stay-up-to-date.html, https://doi.org/10.1001/jamanetworkopen.2021.30479, Centers for Disease Control and Prevention, U.S. Department of Health & Human Services, American Indian or Alaska Native, non-Hispanic, Psychiatric admission requiring medical care. As Omicron spread in the US, hospitalization rates in December were much lower for the vaccinated. 384, 22732282 (2021). Mortal. These trends could result in epidemic phase bias if infection severity is correlated with time from infection to test. the date of publication. provided as a service to MMWR readers and do not constitute or imply BNT162b2 vaccine effectiveness against omicron in children 5 to 11 years of age. As a result, the number of total hospitalizations exceeds the sum of unvaccinated adults, adults who received a primary series without a booster or additional dose, and adults who received a primary series with a booster or additional dose. Kharbanda, E. O. et al. J. Med. Sect. Second, vaccination status is subject to misclassification; this might affect estimation of rates by vaccination status. J. You can review and change the way we collect information below. Objectives To develop and implement a scoring tool to identify COVID-19 patients that are at risk for severe illness during the Omicron wave. All authors reviewed the manuscript. Adults who completed a primary vaccination series were persons who had received the second dose of a 2-dose COVID-19 vaccination series or a single dose of a 1-dose product 14 days before a positive SARS-CoV-2 test associated with their hospitalization but received no booster or additional dose. COVID-19associated signs and symptoms included respiratory symptoms (congestion or runny nose, cough, hemoptysis or bloody sputum, shortness of breath or respiratory distress, sore throat, upper respiratory infection, influenza-like illness, and wheezing) and non-respiratory symptoms (abdominal pain, altered mental status or confusion, anosmia or decreased smell, chest pain, conjunctivitis, diarrhea, dysgeusia or decreased taste, fatigue, fever or chills, headache, muscle aches or myalgias, nausea or vomiting, rash, and seizures). Am. * Information on the impact that booster or additional doses of COVID-19 vaccines have on preventing hospitalizations during Omicron predominance is limited. Christopher A. Taylor, PhD1; Michael Whitaker, MPH1; Onika Anglin, MPH1,2; Jennifer Milucky, MSPH1; Kadam Patel, MPH1,2; Huong Pham, MPH1; Shua J. Chai, MD3,4; Nisha B. Alden, MPH5; Kimberly Yousey-Hindes, MPH6; Evan J. Anderson, MD7,8,9; Kenzie Teno, MPH10; Libby Reeg, MPH11; Kathryn Como-Sabetti, MPH12; Molly Bleecker, MA13; Grant Barney, MPH14; Nancy M. Bennett, MD15; Laurie M. Billing, MPH16; Melissa Sutton, MD17; H. Keipp Talbot, MD18; Keegan McCaffrey19; Fiona P. Havers, MD1; COVID-NET Surveillance Team (View author affiliations). We ran separate models on the time periods associated with the Delta (7/01/2021 to 12/20/2021) and Omicron variants (12/21/2021 to 5/31/2022). They help us to know which pages are the most and least popular and see how visitors move around the site. part 56; 42 U.S.C. The state has administered 3.2 million vaccine doses since Dec. 1 alone, but lagging rates between full vaccination and first doses for adults especially (82.6% vs. 95%) are becoming a point of . KPNC members are similar to the broad catchment population in Northern California in terms of sociodemographic characteristics34. SARS-CoV-2 infection can lead to severe illnesses and hospitalizations in children and infants2,3,4,5. 387, 109119 (2022). J. Med. The report shows people catching Omicron are: 31% to 45% less likely to go to A&E. 50% to 70% less likely to be admitted to hospital for treatment. Users are referred to the electronic PDF version (https://www.cdc.gov/mmwr) Vaccine effectiveness for 1 dose during the first 6 months of life was 68% (95% CI: 12, 88) (Table2). We conducted secondary sensitivity analyses restricting the population to infants who received at least one SARS-CoV-2 PCR test. CDC graphs show in detail the protection vaccines gave from hospitalization. TN, NMF, WH, and SA wrote the software. Although the study was unable to directly estimate VE against hospitalization due to the small number of hospitalized cases, it found that over the entire study period, the incidence rate of hospitalization during the first 6 months of life was much lower among the infants whose mothers were vaccinated during pregnancy compared with those whose mothers were not vaccinated. Mortal. Nature. Laurie M. Billing and Kenzie Teno report grants from the Council of State and Territorial Epidemiologists during the conduct of the study. NMF, SB, SFunk, ACG, DDA, and AMP acquired funding. Delta period: July 1, 2021December 18, 2021, reflects the time when Delta was the predominant circulating variant; Omicron period: December 19, 2021January 31, 2022, reflects the time when Omicron was the predominant circulating variant. Other studies found similarly decreased proportions of severe outcomes among hospitalized patients with COVID-19 during this period (6).. While Omicron caused a big spike in COVID-19 cases, vaccinated people continued to be less likely to be hospitalized than the unvaccinated. Evaluation of the relative virulence of novel SARS-CoV-2 variants: a retrospective cohort study in Ontario, Canada. 384, 403416 (2021). Vaccines: The CDC recommends that everyone age 5 and older get an updated covid booster shot. Over the entire study period, the incidence of hospitalization for COVID-19 was lower during the first 6 months of life among infants of vaccinated mothers compared with infants of unvaccinated mothers (21/100,000 person-years vs. 100/100,000 person-years). Using Cox regression, the effectiveness of 2 doses of COVID-19 vaccine received during pregnancy was 84% (95% confidence interval [CI]: 66, 93), 62% (CI: 39, 77) and 56% (CI: 34,71) during months 02, 04 and 0- 6 of a childs life, respectively, in the Delta variant period. and JavaScript. The development of a standardized neighborhood deprivation index. Late last year, as Omicron was spreading fast in the US, hospitalization rates per 100,000 rose sharply among unvaccinated adults, while rates in those who were fully vaccinated remained. During the proxy omicron period, we found a vaccine effectiveness of 70% (95% confidence interval . To ensure stability and reliability of rates by vaccination status, data are presented beginning when 14 days have passed since at least 5% of the population of adults aged 18 years in the COVID-NET surveillance catchment area had received an additional or booster dose. Frequency, characteristics and complications of COVID-19 in hospitalized infants. Iowa does not provide data on vaccination status. Morb. Selected counties in California, Colorado, Connecticut, Georgia, Maryland, Michigan, Minnesota, New Mexico, New York, Ohio, Oregon, Tennessee, and Utah (https://www.cdc.gov/mmwr/volumes/69/wr/mm6915e3.htm). Omicron vaccine effectiveness estimates for 7 to 59 days, 60 to 119 days, and 240 days or more after the second dose are not presented owing to imprecision in the estimates and wide 95% CIs (ie, 100 percentage points). The cumulative monthly age-adjusted hospitalization rate during January 2022 among unvaccinated adults (528.2) was 12 times the rates among those who had received a booster or additional dose (45.0) and four times the rates among adults who received a primary series, but no booster or additional dose (133.5). To ensure stability and reliability of rates by vaccination status, data are presented beginning 14 days after at least 5% of the age group-specific population of the COVID-NET surveillance catchment area has received an additional or booster dose. Messer, L. C. et al. Department of Health and Human Services. Article Centers for Disease Control and Prevention. Models in this analysis were adjusted for the same covariates included in the primary analysis. 384, 21872201 (2021). All other authors declare no competing interests. PubMed https://www.medrxiv.org/content/10.1101/2021.08.27.21262356v1 Compared with the Delta-predominant period, the proportion of unvaccinated hospitalized Black adults increased during the Omicron-predominant period. The study was funded by the National Institute of Allergy and Infectious Disease grant # 1R01AI168373-01 to O.Z. 1). as well as other partner offers and accept our. J. Med. Maryland did not contribute data after December 4, 2021, but did contribute data for previous weeks. Adults with no documented receipt of any COVID-19 vaccine dose before the test date were considered unvaccinated. Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of PubMed The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website. Protection during both periods decreased as infants aged. Two to 4 weeks after a booster dose, vaccine effectiveness ranged from around 65-75%, dropped to 55-70% at 5 to 9 weeks, and 40-50% from 10 weeks or more after a booster dose. The study had limitations worth noting. CDC is not responsible for the content The company also said full results of its 2,250-person study confirmed the pill's promising early results against the virus: The drug reduced combined hospitalizations and deaths by about 89. The report found that, during the omicron wave 6,743.5 per 100,000 unvaccinated people were contracting COVID-19 and 187.8 per 100,000 were hospitalized. We thank staff at UKHSA and members of the UK Government SPI-M committee and the UKHSA Variant Technical Group for valuable discussions. N. Engl. **** ICU admission and IMV are not mutually exclusive categories, and patients could have received both. 26 Among those fully vaccinated individuals 5 years of age who are booster eligible, only 49% have received a . The final study population included 30311 (48.8%) infants who were KPNC members at least 2 months after birth. However, we have no reason to expect a strong association between the absence of NHS number and SARS-CoV-2 variant. Introduction: A rapid increase in COVID-19 cases due to the spread of the Delta and Omicron variants in vaccinated populations has raised concerns about the hospitalization risk associated with, and the effectiveness of, COVID-19 vaccines. Rates are calculated using the CDC National Center for Health Statistics vintage 2020 bridged-race postcensal population estimates for the counties included in surveillance. The average age of participants was 60.8 years, and 92.0% were White. On 13 December, Denmark released data showing that hospitalization rates for people infected with Omicron seemed to be on a par with those for people infected with other variants. American Academy of Pediatrics. However, data currently available on the persistence of immunity after vaccination on the one hand and the emergence of viral variants with reduced sensibility to vaccine immunity on the other, raise the need to administer boosters to maintain the protection and to compare . Third, because immunocompromise status is not always known, it is not possible to distinguish between booster and additional doses; this could have influenced observed rates. Pre-Omicron versions of Covid, in. Sect. PubMed Central During the Omicron-predominant period, weekly COVID-19associated hospitalization rates (hospitalizations per 100,000 adults) peaked at 38.4, compared with 15.5 during Delta predominance. The results were unchanged when no adjustments for covariates were made (Supplemental Table3). It showed that boosters further reduced the risk of hospitalization. Vaccinations were limited only to those received during pregnancy. Children and COVID-19: state data report. Baden, L. R. et al. Foo, D., Sarna, M., Pereira, G., Moore, H. C. & Regan, A. K. Longitudinal, population-based cohort study of prenatal influenza vaccination and influenza infection in childhood. Halasa, N. B. et al. As with previous variants, being vaccinated greatly protects you from severe disease with omicron. 385, 13551371 (2021). Risk factors for severe COVID-19 in children. Like influenza and Tdap vaccines15,16, data suggest that vaccination during pregnancy may protect infants who are not old enough to be vaccinated against COVID-19. Most QCovid risk groups were tied to an increased risk of post-booster death, except congenital heart disease, asthma, and previous fracture. *** An additional 172 (3.4%, 95% CI = 2.7%4.2%) adults were partially vaccinated, 69 (0.9%, 95% CI=0.61.2) received a primary vaccination series <14 days before receiving a positive SARS-CoV-2 test result, and 186 (4.1%) had unknown vaccination status; these groups are not further described in this analysis. Adults who received booster doses were classified as those who completed the primary series and received an additional or booster dose on or after August 13, 2021, at any time after completion of the primary series, and 14 days before a positive test result for SARS-CoV-2, because COVID-19associated hospitalizations are a lagging indicator and time passed after receipt of a booster dose has been shown to be associated with reduced rates of COVID-19 infection (https://www.nejm.org/doi/full/10.1056/NEJMoa2114255). Nursing home residents have been disproportionately affected by COVID-19; older age, comorbidities, and the congregate nature of nursing homes place residents at higher risk for infection and severe COVID-19-associated outcomes . PubMed Dagan, N. et al. Abbreviations: COVID-NET = COVID-19Associated Hospitalization Surveillance Network; ICU=intensive care unit; IMV=invasive mechanical ventilation; LTCF=long-term care facility; NA = not applicable. E. & Klein, N. P. Effectiveness of vaccination during pregnancy to prevent infant pertussis. Vaccine 35, 72977301 (2017). These findings are consistent with estimates of booster effectiveness against symptomatic Omicron infection using healthcare ascertainment. Suggested citation for this article: Taylor CA, Whitaker M, Anglin O, et al. Covid-19 vaccine effectiveness against the Omicron (B.1.1.529) variant. MMWR Morb Mortal Wkly Rep 2022;71:1328. Sign up for the Nature Briefing newsletter what matters in science, free to your inbox daily. Article 182, 825831 (2022). Racial and ethnic disparities in rates of COVID-19associated hospitalization, intensive care unit admission, and in-hospital death in the United States from March 2020 to February 2021. It is not inevitable that viral evolution leads to lower severity. These persons are excluded from the proportions of race/ethnicity but are included in other analyses. Persons who received only 1 vaccine dose of a 2-dose series 14 days before the SARS-CoV-2 test date or had received a single dose of either a 1- or 2-dose vaccination series <14 days before the positive SARS-CoV-2 test result were considered partially vaccinated and were not included in rates by vaccination status. 383, 26032615 (2020). 4% of cases) without NHS numbers were excluded from our primary analysis. In-hospital death status was missing in 1.4% (weighted) of hospitalizations; these hospitalizations are otherwise included elsewhere in the analysis. According to the CDC, hospitalization rates among the unvaccinated were 16 times higher in December overall. Maternal vaccination was protective, but protection was lower during Omicron than during Delta. TN, NMF, SFlax, MC, DDA, AMP, and ST conceptualised the work. Additional limitations include the inability to estimate the effectiveness of vaccines received prior to pregnancy onset. COVID-19 vaccines have demonstrated both high efficacy in clinical trials and high real-world effectiveness, especially against the original and Delta variant of the virus6,7,8,9,10. Hospitalization rates and characteristics of children aged <18 years hospitalized with laboratory-confirmed COVID-19COVID-NET, 14 States, March 1-July 25, 2020. The Lancet Regional Health Southeast Asia, The Lancet Regional Health Western Pacific, 36-fold higher estimate of deaths attributable to red meat intake in GBD 2019: is this reliable? Carlsen, E. O. et al. The rate among adults who received a primary series, but no booster or additional dose, was three times the rate among adults who received a booster or additional dose. The TND is designed to better control for bias related to health care-seeking behavior31,32. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. In conclusion, in this population-based cohort study, we found that infants born to mothers who received at least two doses of an mRNA COVID-19 vaccine during pregnancy were at lower risk of testing positive for SARS-CoV-2 and were at lower risk of hospitalization during the first 6 months of life compared with infants whose mothers were unvaccinated during pregnancy. During the Omicron dominant period, maternal vaccination with at least two doses reduced the infants risk of testing SARS-CoV-2 positive by 43% (95% CI: 4, 69) during the first 2 months of life, 36% (95% CI:11, 55) during the first 4 months of life, and 41% (95% CI: 25, 53) during the first 6 months of life (Supplemental Table2). Health and Human Services. In King County, Wash., which includes Seattle, unvaccinated people were 13 times more likely to be hospitalized for coronavirus since December than people who were fully vaccinated.