It is possible that this practice may have led to some misclassification of the outcome, and we were unable to assess whether this misclassification was differential between vaccinated and unvaccinated mothers. During Omicron predominance, children aged <6 months accounted for 44% of hospitalizations among children ages 04 years3. COVID is still killing people every day. But its main victims have Mortal. We monitored the seroprevalence of SARS-CoV-2 nucleocapsid (anti-N) and spike protein (anti-S) antibodies in blood donors across Canada from September 2021 to June 2022 in 202,123 . COVID-19 incidence and death rates among unvaccinated and fully vaccinated adults with and without booster doses during periods of Delta and Omicron variant emergence25 U.S. Jurisdictions, April 4December 25, 2021. NMF, SB, SFunk, ACG, DDA, and AMP acquired funding. Receipt of COVID-19 vaccine during pregnancy and preterm or small-for-gestational-age at birtheight integrated Health Care Organizations, United States, December 15, 2020-July 22, 2021. You can review and change the way we collect information below. Methods: One hundred and . Vaccinated patients during the Delta wave were 37% (over with two doses), while during the Omicron wave they were 57%. But the charts are in line with data from the UK Health Safety Agency, which found that protection from a third dose of Pfizer or Moderna vaccine against hospitalization with Omicron was about 89%, waning slightly to 83% at 10 weeks, Insider's Catherine Schuster Bruce reported. * https://covid.cdc.gov/covid-data-tracker/#variant-proportions, https://www.cdc.gov/coronavirus/2019-ncov/covid-data/covid-net/purpose-methods.html. Google Scholar. Zerbo, O., Ray, G.T., Fireman, B. et al. During the study period, the omicron variant experienced a rapidly increasing incidence, whereas the delta variant was experiencing a decreasing or less rapidly increasing incidence. Mothers were classified as either having had 2 doses or one dose of mRNA COVID-19 vaccines during pregnancy (and completed more than 14 days prior to delivery) or not having had any COVID-19 vaccines prior to delivery. These proportions are lower compared with 47.3% of White persons who received a primary series and 54.5% of eligible adults who received a booster dose. Relative to the Delta-predominant period, Black adults accounted for a larger proportion of unvaccinated adults during the Omicron-predominant period, and age-adjusted hospitalization rates for Black adults increased to the highest rate among all racial and ethnic groups for any week during the pandemic. However, in contrast with the Norwegian study which reported that infants of mothers who were vaccinated had a 33% decreased risk of testing positive during the first 4 months of life during the Omicron period17, our study found a 13% reduced risk that was not statistically significant. Most mothers (1032 of 1138) who received only one dose received the vaccine during the third trimester. Cohen-Stavi, C. J. 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. Kharbanda, E. O. et al. The study was funded by the National Institute of Allergy and Infectious Disease grant # 1R01AI168373-01 to O.Z. Google Scholar. As of January 26, 2022, 39.6% of Black persons received a primary vaccine series; of those, 43.9% of adults received a booster dose once eligible. All adjustment variables were selected a priori based on prior work36. Med. 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. Am. J. Med. In the Omicron variant period, the effectiveness of maternal vaccination in these three age intervals was 21% (CI: 21,48), 14% (CI: 9,32) and 13% (CI: 3,26), respectively. Omicron Is Not More Severe for Children, Despite Rising During the Omicron-predominant period, peak hospitalization rates among non-Hispanic Black (Black) adults were nearly four times the rate of non-Hispanic White (White) adults and was the highest rate observed among any racial and ethnic group during the pandemic. J. Med. Although hospitalization rates increased for all adults, rates were highest among unvaccinated adults and lowest among adults who had received a primary series and a booster or additional dose. Evaluation of the relative virulence of novel SARS-CoV-2 variants: a retrospective cohort study in Ontario, Canada. Thank you for taking the time to confirm your preferences. and statistical significance was assessed at two-sided p0.05. NEW YORK and MAINZ, GERMANY, March 1, 2023 Pfizer Inc. (NYSE: PFE) and BioNTech SE (Nasdaq: BNTX) today submitted an application to the U.S. Food and Drug Administration (FDA) for Emergency Use Authorization (EUA) of a booster (fourth) dose of the companies' Omicron BA.4/BA.5-adapted bivalent COVID-19 vaccine in children 6 months through 4 years of age (also referred to as under 5 years). Two recent papers claim there are no differences between surgical masks and respirators for preventing the spread of respiratory diseases like COVID-19 and flu, but the articles are deeply flawed. However, linking is sometimes not possible because CDC does not receive personally identifiable information about vaccine doses. SARS-CoV-2 infections can result in COVID-19associated hospitalizations, even among vaccinated persons. NMF, MC, GD, DDA, AMP, and ST supervised the work. Baden, L. R. et al. It is possible that our exclusion criteria may have resulted in a final sample that may not be reflective of all KPNC infants. Overall, the study results support recommendations for vaccination during pregnancy to protect both mothers and their infants. This is a relevant consideration because vaccines can be less effective in persons with a weakened immune system. The population of unvaccinated adults is determined by subtracting the number of adults who received any dose of vaccine, as previously defined, from the population. 387, 227236 (2022). Morb. N. Engl. Variances were estimated using Taylor series linearization method. provided as a service to MMWR readers and do not constitute or imply
In this primary design, all eligible infants meeting inclusion criteria were included without sampling which improved power and minimized bias related to selection. TN, NMF, SGN, DDA, AMP, and ST wrote the original draft of the manuscript. Iowa does not provide data on vaccination status. The aim of the secondary design was to compare the results of the cohort with TND. Recently another study reported that the effectiveness of mRNA COVID-19 vaccines against infections and hospitalizations among pregnant people was higher during the Delta period than during the Omicron period21. Relative to the Delta-predominant period, a larger proportion of hospitalized Black adults were unvaccinated. CDC twenty four seven. We also conducted analyses based on the trimester during which the vaccine was received during pregnancy (first, second, or third trimester). We use cookies to help provide and enhance our service and tailor content and ads. 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. It is not inevitable that viral evolution leads to lower severity. Article Sample sizes presented are unweighted with weighted percentages. Cookies used to make website functionality more relevant to you. First, COVID-19associated hospitalizations might have been missed because of hospital testing practices and test availability. Our findings that receipt of at least two doses of COVID-19 vaccine during pregnancy was effective at protecting infants during the Delta period are similar to those reported in a recent Norwegian study showing that mRNA COVID-19 vaccination during pregnancy was associated with a 71% decreased risk of testing positive for SARS-CoV-2 in infants during their first 4 months of life during the Delta period17. Starting the week ending December 4, 2021, Maryland data are not included in calculations but are included in previous weeks. 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). BNT162b2 mRNA Covid-19 vaccine in a nationwide mass vaccination setting. COVID-19Associated Hospitalizations Among Adults During SARS-CoV-2 Delta and Omicron Variant Predominance, by Race/Ethnicity and Vaccination Status COVID-NET, 14 States, July 2021January 2022. Compared with the Delta-predominant period, the proportion of unvaccinated hospitalized Black adults increased during the Omicron-predominant period. Beginning the week of December 1925, 2021, the B.1.1.529 (Omicron) variant of SARS-CoV-2 (the virus that causes COVID-19) became the predominant circulating variant in the United States (i.e., accounted for >50% of sequenced isolates). Sign up for notifications from Insider! By clicking Sign up, you agree to receive marketing emails from Insider Most mothers (66.14%) were between ages 25 and <35 years, and more than a quarter (27.27%) were of Asian race, 5.16% were Black, 24.44% were of Hispanic ethnicity and 37.57% were White. Informed consent was waived because this was a data-only study with no direct contact with participants. J. Med. Our study was strengthened both by its large sample size and our ability to follow infants through 6 months of age. Among fully vaccinated people without a booster, rates were lower at 3,355.5 per 100,000 for COVID-19 cases and 35.4 per 100,000 for hospitalizations. Among children 12 to 17, the . 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. Morb. The funders played no direct role in the study. CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. Publishers note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Relative to the Delta-predominant period, a significantly shorter median length of hospital stay was observed during the Omicron-predominant period and smaller proportions of hospitalizations with intensive care unit admission, receipt of invasive mechanical ventilation, or in-hospital death. This conversion might result in character translation or format errors in the HTML version. We, therefore, were unable to assess whether maternal infection provided some protection to their infants. J. Med. Google Scholar. **** ICU admission and IMV are not mutually exclusive categories, and patients could have received both. Infect. DeSilva, M. et al. To account for the correlation between infants with the same mother, we fit marginal Cox proportional hazards models using robust sandwich variance estimates. 4% of cases) without NHS numbers were excluded from our primary analysis. During the Delta dominant period, the crude incidences of testing positive for SARS-CoV-2 during the first 2, 4, and 6 months of life were lower among infants whose mothers received at least two doses of mRNA COVID-19 vaccines during pregnancy (0.75, 1.43, and 1.56 infants per 100 person-years [PY], respectively) than those whose mothers were not vaccinated during pregnancy (5.47, 5.10, and 4.78 infants per 100 PYs, respectively). How the Omicron Surge Is Taxing Hospitals - Healthline Wkly Rep. 71, 352358 (2022). Hospitalization of infants and children aged 0-4 years with laboratory-confirmed COVID-19COVID-NET, 14 states, March 2020-February 2022. Our primary cohort analysis used calendar days as the underlying scale to ensure that we compared infants of vaccinated and unvaccinated mothers on the same calendar days because vaccination status during pregnancy and risk of SARS-CoV-2 infection varied over the study period. Mortal. Vaccines and Omicron mean Covid now less deadly than flu in England All adults should stay up to date with COVID-19 vaccination to reduce their risk for COVID-19associated hospitalization. The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website. 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. 9-14 As of October 2022, 68% of the US population has completed primary series vaccination. Vaccine 35, 72977301 (2017). Acosta AM, Garg S, Pham H, et al. Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. 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 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. Between December 15, 2020, and May 31, 2022, we identified 62,117 infants born at Kaiser Permanente Northern California (KPNC), an integrated healthcare delivery organization. The final study population included 30311 (48.8%) infants who were KPNC members at least 2 months after birth. Structural changes in the brain may explain the persistent fatigue and neuropsychiatric complications tied to long COVID. The study setting was Kaiser Permanente Northern California (KPNC), an integrated healthcare delivery organization that provides comprehensive healthcare to ~4.4 million members as of 2019. Nat Commun 14, 894 (2023). You will be subject to the destination website's privacy policy when you follow the link. #FridayNight | #FridayNight | By Citizen TV Kenya | Facebook | Good About half of long-COVID patients who were on sick leave at 4 months were still on sick leave at 2 years. Schrag, S. J. et al. South Africa omicron crisis: Cases, hospitalizations and - CNBC https://www.cdc.gov/mmwr/volumes/70/wr/mm7050e2.htm, Adults who completed their primary COVID-19 vaccination series were defined as those who had received the second dose of a 2-dose primary vaccination series or a single dose of a 1-dose primary vaccine product 14 days before receipt of a positive SARS-CoV-2 test result associated with their hospitalization but received no additional or booster dose. It showed that boosters further reduced the risk of hospitalization. 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). Starting the week ending December 4, 2021, Maryland data are not included in weekly rate calculations but are included in previous weeks. Experts say they. MMWR Morb Mortal Wkly Rep 2021;70:108893. https://downloads.aap.org/AAP/PDF/AAP%20and%20CHA%20-%20Children%20and%20COVID-19%20State%20Data%20Report%209.29.22%20FINAL.pdf?_ga=2.255000394.335550773.1665001859-370326403.1636740765 (2022). A recent study found that the mean titer of maternally derived antibodies in infants of vaccinated mothers were higher at age 2 months compared with antibody titers at age 6 months23. Top editors give you the stories you want delivered right to your inbox each weekday. Klein, N. P. et al. MMWR Morb Mortal Wkly Rep 2022;71:1328. 384, 21872201 (2021). 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. Severe cases may increase in the wake of holiday parties where people of all ages mixed. You are using a browser version with limited support for CSS. Danino, D. et al. JAMA 327, 10871089 (2022). The images or other third party material in this article are included in the articles Creative Commons license, unless indicated otherwise in a credit line to the material. When possible, CDC associates a persons primary vaccination series and booster dose with that person. The success of Covid-19 vaccines against omicron: Vaccinated up to five The outcomes were the infants first positive nasal/throat swab for SARS-CoV-2 by PCR, and the first COVID-19-related hospitalization, occurring during the first 6 months of life and recorded in the electronic health record. The objective of this study was to further evaluate the effectiveness of at least two doses of mRNA COVID-19 vaccination during pregnancy for preventing SARS-CoV-2 infection in infants during the first 2, 4, and 6 months of life during the Delta and Omicron variant periods. All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. MMWR Morb Mortal Wkly Rep 2022;71:466473. Additional recommendations followed and data availability on booster-dose status varies by age because not all age groups were recommended by ACIP to receive booster doses at the same time. Risk was especially high for people with severe combined immunodeficiency (HR, 6.2). Secondarily, we used a Test-Negative Design (TND), which is a case-control study, to compare the odds of vaccination among mothers of infants who tested positive vs. the odds of vaccination among mothers of infants who tested negative. The difference between the two studies might be due to population characteristics and the timing of follow-up as ours went through May 31, 2022, while the Norwegian study ended in April 2022. 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. Marks, K. J. et al. Vaccine effectiveness of cell-culture relative to egg-based inactivated influenza vaccine during the 2017-18 influenza season. Lipkind, H. S. et al. Durability of anti-spike antibodies in infants after maternal COVID-19 vaccination or natural infection. N. Engl. Biomedicines | Free Full-Text | Risk Stratification Model for Severe Dis. Omicron up to 70% less likely to need hospital care - BBC News 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. E.L. coordinated administrative tasks. Data were available for researchers who meet the criteria for access to Kaiser Permanente Northern California confidential data. Wkly. All HTML versions of MMWR articles are generated from final proofs through an automated process. Vaccine 31, 31043109 (2013). The findings in this report are subject to at least four limitations. Hospitalization rates and characteristics of children aged <18 years hospitalized with laboratory-confirmed COVID-19COVID-NET, 14 States, March 1-July 25, 2020. Hospitalization rates during peak Omicron circulation (January 2022) among unvaccinated adults remained 12 times the rates among vaccinated adults who received booster or additional doses and four times the rates among adults who received a primary series, but no booster or additional dose. Sect. Get the most important science stories of the day, free in your inbox. They, as well as vaccinated people who are immunocompromised and at higher risk of severe COVID-19, are still vulnerable to being infected by a vaccinated person. The development of a standardized neighborhood deprivation index. These data should be taken with a grain of salt. TN, NMF, SFlax, MC, DDA, AMP, and ST conceptualised the work. Viruses | Free Full-Text | SARS-CoV-2 Seroprevalence among Canadian PubMed Central Mountain lions, a bobcat, red foxes, black bears, and skunks represent the latest avian flu cases in mammals. Omicron Is Not More Severe for Children, Despite Rising Hospitalizations More children are being treated for Covid, but a combination of factors, including low vaccination rates, most. the date of publication. Maryland did not contribute data after December 4, 2021, but did contribute data for previous weeks. 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. However, protection estimates greater than 90% might be too high if individuals with a previous infection were more likely than those without one to come forward for a test for reasons other than suspicion of COVID-19. This analysis describes weekly hospitalization rates during Delta- and Omicron-predominant periods. Slider with three articles shown per slide. The stats are for COVID-associated hospitalizations, which may include people for whom COVID-19 was not the primary reason for admission. ***** 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 a positive for SARS-CoV-2 test result, and 186 (4.1%) had unknown vaccination status; these groups are not further described in this analysis. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Weekly / March 25, 2022 / 71(12);466473. 189, 13791388 (2020). Safety and efficacy of single-dose Ad26.COV2.S vaccine against Covid-19. Zerbo, O. et al. Omicron data in UK is 'enormously worrying,' immunologist says "In the last two weeks, no fewer than 80% of admissions were below the age of 50 years. Dis. References to non-CDC sites on the Internet are
Vaccination status is based on state immunization information system data. Starting the week ending December 4, 2021, Maryland data are not included in weekly rate calculations but are included in previous weeks. 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. J. Med. 182, 825831 (2022). Models in this analysis were adjusted for the same covariates included in the primary analysis. Vaccination status (unvaccinated, receipt of a primary series only, or receipt of a primary series plus a booster or additional dose) was determined for individual hospitalized patients and for the catchment population using state immunization information systems data (2). Chi-square tests were used to compare differences between the Delta- and Omicron-predominant periods; p-values <0.05 were considered statistically significant. Age-adjusted hospitalization rates among Black adults peaked at 94.7 (January 8, 2022), higher than that among all other racial and ethnic groups, 3.8 times the rate among White adults (24.8) for the same week, and 2.5 times the previous peak (January 16, 2021) among Black adults (37.2). N. Engl. There were only one hospitalized case among the children of vaccinated mothers and nine hospitalized cases among the children of unvaccinated mothers (Table1). For children whose mothers received one dose before pregnancy and two doses during pregnancy, VE against infection was 89% during the first 2 months of life, 73% during the first 4 months of life, and 48% up to 6 months of life. 41, e81e86 (2022). Article Waning 2-dose and 3-dose effectiveness of mRNA vaccines against COVID-19-associated emergency department and urgent care encounters and hospitalizations among adults during periods of delta and omicron variant predominanceVISION Network, 10 states, August 2021-January 2022. PubMed 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. During the Omicron-predominant period, hospitalization rates increased among unvaccinated persons and those who completed a primary series, with and without receipt of a booster or additional dose (Figure 2). Dagan, N. et al. conducted all statistical analysis in collaboration with O.Z. COVID-19 vaccination during pregnancy: coverage and safety. Implementing strategies that result in the equitable receipt of COVID-19 vaccinations among persons with disproportionately higher hospitalizations rates, including non-Hispanic Black adults, is an urgent public health priority. This work was supported by grants from the UK Research and Innovation (UKRI) Medical Research Council (NMF, WH, SB, EV, ACG [Centre for Global Infectious Disease Analysis; MR/R015600/1], DDA, AMP [MC/UU/00002/11], and SRS [MC/UU/00002/10]); Medical Research Council UKRIDepartment of Health and Social Care National Institute for Health Research (NIHR) COVID-19 rapid response call (NMF, SB [MR/V038109/1], TN, AC, DDA, and AMP [MC/PC/19074]); the NIHR Health Protection Units in: Modelling and Health Economics (NMF, WH, SB, EV, AC, and ACG [NIHR200908]), Behavioural Science and Evaluation (AC and DDA), and Respiratory Infections (JLB); Wellcome Trust (SFunk and SA [210758/Z/18/Z]); philanthropic funding from Community Jameel (NMF, WH, SB, and EV); and the UKRI Engineering and Physical Sciences Research Council (SFlax [EP/V002910/2]). "People who get vaccinated may be more cautious about COVID in general, or perhaps getting vaccinated makes them less cautious, or they may live in states with more/less COVID risk, etc," Jit said. On the bias of estimates of influenza vaccine effectiveness from test-negative studies. J. Med. In-hospital death status was missing in 1.4% (weighted) of hospitalizations; these hospitalizations are otherwise included elsewhere in the analysis. Wkly. PubMedGoogle Scholar. COVID Data Tracker Weekly Review | CDC The data cannot be shared publicly because the data contain potentially identifying or sensitive patient information and is legally restricted by Kaiser Permanente Northern California. Relative to the Delta-predominant period, the proportion of cases in non-Hispanic Asian or Pacific Islanders also increased, whereas the proportion in all other racial and ethnic groups decreased. These findings are consistent with estimates of booster effectiveness against symptomatic Omicron infection using healthcare ascertainment. Methods: This is a retrospective cohort study that was conducted in Israel's second-largest . wrote the initial manuscript. O.Z., N.P.K., and B.F. conceived and designed the study. PubMed Delahoy MJ, Whitaker M, OHalloran A, et al. In the meantime, to ensure continued support, we are displaying the site without styles Initial hospital data from England and Denmark also suggest Omicron cases are less severe. 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. 3501 et seq. Ousseny Zerbo. In January 2022, unvaccinated adults and those vaccinated with a primary series, but no booster or additional dose, were 12 and three times as likely to be hospitalized, respectively, as were adults who received booster or additional doses.