The following is a summary of “Incidence of COVID-19 mRNA vaccine symptomatic breakthrough infections during Omicron circulation in adults with or without infection prior to vaccination,” published in the March 2024 issue of Infectious Diseases by Durier et al.
Breakthrough COVID-19 infections were common with the Omicron variant. The ANRS|MIE CoviCompareP study looked at these infections in adults who got the Pfizer-BioNTech (BNT162b2) vaccine, with or without a prior COVID-19 infection.
Researchers conducted a prospective study to understand breakthrough infections in adults who received the BNT162b2 vaccine, considering prior COVID-19 infection status.
They used healthy adults between 18-45, 65-74, and >75 years old to receive either one dose of BNT162b2 (n = 120) based on past infection within at least five months or two doses (n = 147) if reported no history verified by serological testing. A booster dose was administered at least 6 months after primary vaccination. Assessing neutralizing antibodies against the D614G and Omicron BA.1 variant was done up to 28 days after the first booster dose. A case-controlled analysis was also performed for the 252 participants in 2022.
The results showed 78/252 (31%) (21/117 [18%] infected and 57/135 [42%] not infected before vaccination) participants experienced a symptomatic breakthrough infection after complete vaccination (January and October 2022). The multivariate logistic regression model showed factors linked with lower breakthrough infection were older age, more booster doses, and higher levels of omicron BA.1NAb titers with previous infection, but not in those without prior infection.
Investigators found it crucial to consider immune markers of protection, infection, and vaccination history.
Source: sciencedirect.com/science/article/pii/S2666991924000411