Symptoms Six Weeks After COVID-19 Are Reduced Among US Health Care Personnel Receiving Additional Vaccine Doses During the Omicron Period, December 2021-April 2022

Abstract

Background: The objective of this study was to test the hypothesis that subsequent doses of the coronavirus disease 2019 (COVID-19) vaccine are associated with lower incidence of COVID-19-like symptoms at 6 weeks after infection.

Methods: This study was a case-control analysis of health care personnel in an ongoing multicenter COVID-19 vaccine effectiveness study. We enrolled participants at the time of COVID-19-like symptoms between December 19, 2021, and April 27, 2022, which corresponded to the early Omicron-predominant period after original monovalent severe acute respiratory syndrome coronavirus 2 additional vaccination doses became available. Our outcome was self-reported symptoms completed 6 weeks after the onset of symptoms.

Results: We enrolled 2478 participants, of whom 1422 (57%) had COVID-19. The prevalence of symptoms at 6 weeks was 26% (n = 373) in those with COVID-19 and 18% (n = 195) in those without COVID-19. Fatigue (11%) and difficulty sleeping (7%) were most strongly associated with COVID-19. A total of 1643 (66%) participants received a subsequent vaccine dose (after the primary series). Participants with COVID-19 who had received a subsequent vaccination had lower odds of symptoms at 6 weeks (adjusted odds ratio [aOR], 0.55; 95% CI, 0.43-0.70), but this relationship was not observed in those without COVID-19 (aOR, 0.87; 95% CI, 0.59-1.29).

Conclusions: Health care personnel who received subsequent doses of original monovalent COVID-19 vaccine had a lower prevalence of symptoms at 6 weeks than those that did not.

Keywords: COVID-19; COVID-19 vaccines; post-acute COVID-19 syndrome; vaccine efficacy.

Figure 1.

Flow diagram of US health care personnel, December 2021 to April 2022. Abbreviations: COVID-19, coronavirus disease 2019; HCP, health care personnel; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.

Figure 2.

Frequency of symptoms at 6 weeks by SARS-CoV-2 infection and monovalent vaccine status. “Positive” and “negative” relate to the results of the SARS-CoV-2 test at the time of enrollment. “Nonboosted” means that participants had received 2 doses of an mRNA primary SARS-CoV-2 vaccination series, and “boosted” means that participants had additionally received an original monovalent mRNA SARS-CoV-2 vaccine dose. Error bars show the upper limit of the 95% CI. Prolonged symptoms include any symptom reported on the 6-week symptom survey; positive, SARS-CoV-2 positive; negative, SARS-CoV-2 negative; nonboosted, received 2 doses of mRNA vaccine as primary series; boosted, received 2 doses of mRNA vaccine plus an additional dose of original monovalent mRNA COVID-19 vaccine. Positive – HCP who had a positive SARS-CoV-2 test at enrollment. Negative – HCP who had a negative SARS-CoV-2 test at enrollment. Abbreviations: CDC, Centers for Disease Control and Prevention; COVID-19, coronavirus disease 2019; GI, gastrointestinal; HCP, health care personnel; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.