Post COVID-19 condition after Wildtype, Delta, and Omicron SARS-CoV-2 infection and prior vaccination: Pooled analysis of two population-based cohorts

Abstract

Background Post COVID-19 condition (PCC) is an important complication of SARS-CoV-2 infection, affecting millions worldwide. This study aimed to evaluate the prevalence and severity of post COVID-19 condition (PCC) with novel SARS-CoV-2 variants and after prior vaccination. Methods We used pooled data from 1350 SARS-CoV-2-infected individuals from two representative population-based cohorts in Switzerland, diagnosed between Aug 5, 2020, and Feb 25, 2022. We descriptively analysed the prevalence and severity of PCC, defined as the presence and frequency of PCC-related symptoms six months after infection, among vaccinated and non-vaccinated individuals infected with Wildtype, Delta, and Omicron SARS-CoV-2. We used multivariable logistic regression models to assess the association and estimate the risk reduction of PCC after infection with newer variants and prior vaccination. We further assessed associations with the severity of PCC using multinomial logistic regression. To identify groups of individuals with similar symptom patterns and evaluate differences in the presentation of PCC across variants, we performed exploratory hierarchical cluster analyses. Results We found strong evidence that vaccinated individuals infected with Omicron had reduced odds of developing PCC compared to non-vaccinated Wildtype-infected individuals (odds ratio 0.42, 95% confidence interval 0.24–0.68). The odds among non-vaccinated individuals were similar after infection with Delta or Omicron compared to Wildtype SARS-CoV-2. We found no differences in PCC prevalence with respect to the number of received vaccine doses or timing of last vaccination. The prevalence of PCC-related symptoms among vaccinated, Omicron-infected individuals was lower across severity levels. In cluster analyses, we identified four clusters of diverse systemic, neurocognitive, cardiorespiratory, and musculoskeletal symptoms, with similar patterns across variants. Conclusion The risk of PCC appears to be lowered with infection by the Omicron variant and after prior vaccination. This evidence is crucial to guide future public health measures and vaccination strategies.

Recovery and symptom trajectories up to two years after SARS-CoV-2 infection: population based, longitudinal cohort study

“…Thirdly, participants from the Zurich SARS-CoV-2 Cohort enrolled when wildtype SARS-CoV-2 was the predominant circulating strain and before vaccination. Further research is needed to assess whether similar courses are noted after vaccination5455 or infection with other variants 5657. Fourth, selection might have occurred in the Zurich SARS-CoV-2 Cohort if individuals who were more concerned with their health were more motivated to participate, or if individuals with post-covid-19 condition were more likely to be retained.…”

A systematic review of the evidence on the associations and safety of COVID-19 vaccination and post COVID-19 condition

“…As part of the updated evidence included in this SR, preliminary evidence on the effect of three or more doses and SARS-CoV-2 variants were identified [30,35,40,41]. A third dose of a COVID-19 vaccine may offer additional protection against PCC, however in the two versus three dose analyses, it is unclear whether the additional protection is due to the shorter time between the last vaccine dose received and COVID-19 [30]. Vaccination also appeared to be more protective against PCC in individuals post Omicron infection compared to Delta in some studies [30,41].…”

“…A third dose of a COVID-19 vaccine may offer additional protection against PCC, however in the two versus three dose analyses, it is unclear whether the additional protection is due to the shorter time between the last vaccine dose received and COVID-19 [30]. Vaccination also appeared to be more protective against PCC in individuals post Omicron infection compared to Delta in some studies [30,41]. However, the lack of significant findings within Delta-infected groups may also be due to sample size limitations as the vaccine rollout of dose 1 and 2 was underway and booster doses were not widely available prior to the surge in Delta cases.…”

“…Four studies compared mRNA and adenoviral vector vaccines, three of which found no significant differences between participants who received mRNA vaccines (BNT162b2 or mRNA-1273) and adeno-viral vector vaccines (ChAdOx1 or Ad26.COV2.S) [42,44,48]. However, one study suggested mRNA-1273 reduced The evidence is very uncertain about the effect of three doses of COVID-19 vaccine prior to COVID-19 on the odds of developing PCC in one study [30]. The study was under powered and reported results for the Delta wave and Omicron wave (I 2 = 30.9%), the latter showed an association PCC -mRNA vs adenovirus vaccines [39].…”

Post COVID-19 Condition, Work Ability and Occupational Changes: Results from a Population-based Cohort

“…Additionally, the generalizability of our findings to individuals infected with emerging SARS-CoV-2 variants of concern or who were vaccinated prior to infection is limited, since our participants were all infected with wildtype SARS-CoV-2 and unvaccinated at infection. The risk of PCC and severe health impairment is substantially reduced with vaccination and infection with newer variants, but still present (51)(52)(53)(54). As the impact of PCC on work ability is likely comparable in these contexts, this may have significant socioeconomic implications given that more than 45% of the global population is estimated to have been infected with the Omicron variant (55).…”