Association between virus variants, vaccination, previous infections, and post-COVID-19 risk, 2023, Diexer et al.

[SNT Gatchaman]

Association between virus variants, vaccination, previous infections, and post-COVID-19 risk
Diexer; Klee; Gottschick; Xu; Broda; Purschke; Binder; Frese; Girndt; Hoell; Moor; Gekle; Mikolajczyk

Objectives: The SARS-CoV-2 Omicron variant has spread rapidly and has been the dominant variant since 2022. The course of acute infection, in a vaccinated population, with Omicron is milder compared with earlier variants. However, little is known about how the occurrence of long-term symptoms after Omicron infection compared with other variants is modulated by previous infections and/or vaccinations.

Methods: Participants of the DigiHero study provided information about their SARS-CoV-2 infections, vaccinations, and symptoms 12 or more weeks after infection (post-COVID-19 condition - PCC).

Results: Participants infected with wildtype SARS-CoV-2 had the highest PCC risk (adjusted odds ratio [aOR] 6.44, 95% confidence interval (CI): 5.49; 7.56), followed by participants infected with Alpha and Delta compared with the reference group (individuals infected with Omicron having received three or more vaccinations). Among those infected with a specific variant, the number of preceding vaccinations was not associated with a risk reduction for PCC, whereas previous infection was strongly associated with a lower PCC risk (aOR 0.14, 95% CI 0.07; 0.25).

Conclusions: While infection with Omicron is less likely to result in PCC compared with previous variants, lack of protection by vaccination suggests a substantial challenge for the healthcare system during the early endemic period. In the midterm, the protective effects of previous infections can reduce the burden of PCC.

Link | PDF (International Journal of Infectious Diseases)

 

[SNT Gatchaman]

We observed the highest risk of PCC for unvaccinated participants infected with Wildtype SARS-CoV-2 (adjusted Odds Ratio [aOR]: 6.44, 95% CI 5.49; 7.56), followed by unvaccinated and vaccinated participants infected with the Alpha variant (aOR 5.97, 95% CI 4.00; 8.90 and aOR 5.08, 95% CI 4.28; 6.02) compared with participants infected with the Omicron variant and adjusted for sociodemographic information.

Vaccination offered no meaningful protection against developing PCC in case of an infection.

In contrast, there was a strong evidence that a previous infection reduced the risk of PCC (aOR 0.14, 95% CI 0.07; 0.25).

 

[SNT Gatchaman]

We defined PCC based on the presence of any symptom in the time window ≥ 12 weeks after infection. In the analyses, we considered only the first occurrence of PCC (i.e., we censored further data of participants who developed PCC symptoms after their first infection).

Our data suggest that the risk of PCC is decreased if individuals have had a previous infection but have not developed PCC. This risk reduction did not depend on time since previous infection.

This would be a positive aspect with respect to the long-term perspective on PCC. Another potential explanation could be that individuals, who did not develop PCC after their first infection, have characteristics that lead to a lower risk of developing PCC after subsequent infections.