Neutralizing antibodies were initially lowest among Janssen vaccine recipients, but this all changed 6 months after vaccination.
The COVID-19 pandemic has led to millions of deaths worldwide, and vaccination against the virus is a critical tool for its control. The neutralizing antibody (nAB) response induced by vaccination is strongly correlated with protection against COVID-19, but protection has been shown to wane over time, and there are individual differences in sustained immune protection.
A head-to-head comparison study, published in Scientific Reports, sought to identify individual factors that influence the decline in nABs and understand the impact of COVID-19 vaccine type on nAB response durability.
This study investigated the durability of neutralizing antibodies (nABs) in healthy community volunteers who received three different COVID-19 vaccines: Pfizer-BioNTech (BNT162b2), Moderna (mRNA-1273), and Janssen (Ad26.COV2.S). The study enrolled 498 healthy participants who completed questionnaires and blood draws before vaccination, as well as at 1 month and 6 months after vaccination. nAB titers were quantified using a high throughput pseudovirus assay.
One month after vaccination, Pfizer-BioNTech recipients had an antibody response 21 times higher than those who received Janssen, while Moderna recipients boasted a vaccine response 51 times higher than the Janssen cohort.
However, the results showed that nABs declined over the 6 months of follow-up for recipients of Pfizer-BioNTech and Moderna, while the nABs in Janssen recipients increased significantly. At the 6-month time point, nABs to Janssen were significantly higher than nABs to Pfizer-BioNTech and equivalent to Moderna. Older age was associated with lower nABs for participants who received Pfizer-BioNTech and Janssen, but not for those who received Moderna.
A higher baseline body mass index (BMI) was associated with lower nABs for Janssen recipients, but this trend did not apply to patients who received other vaccines. Women and non-smokers showed higher nABs compared to men and current smokers, respectively.
The study’s findings suggest that the durability of nAB responses differs by vaccine type and several sociodemographic factors. However, the study’s limitations should be noted, including a relatively small sample size for some vaccine types, the absence of data on T-cell immunity, and the use of a pseudovirus assay to measure nAB titers.
Overall, this study contributes to the understanding the neutralizing antibody response durability of and the impact of vaccine type and individual factors on vaccine efficacy. These findings can inform public health decisions around booster recommendations and vaccine deployment strategies.