Researchers from the University of North Carolina and Yale School of Public Health say that the protection following Covid-19 vaccination is not long lasting.¹ And the peak antibody levels were highest with the mRNA vaccines (Moderna and Pfizer-BioNTech) compared to the Oxford-AstraZeneca or J&J vaccines or following natural infection.

This study published in the Proceedings of the National Academy of Sciences analysed the duration of immunity provided by BNT162b2 (Pfizer-BioNTech), mRNA-1273 (Moderna), ChAdOx1 (Oxford-AstraZeneca) and Ad26.COV2.S (Johnson & Johnson/Janssen) and the odds of developing a breakthrough infection after taking the vaccine or a natural infection. The anti-spike protein antibody  (IgG) antibody levels were measured and compared with that induced by the natural infection.

The mRNA vaccines generated more anti-spike antibodies than natural infection, which were protective against breakthrough infections for longer duration of time amounting to nearly 30 months (median) compared to the protection offered by the natural infection, which was for 21.5 months (median).

However, the anti-spike antibody levels produced by the viral vector vaccines (Oxford-AstraZeneca and J&J) and the natural infection were comparable. The duration of protection was also shorter than that seen with the mRNA vaccines. The viral vector vaccines were protective for 22.4 months (median), while the natural infection was protective for 20.5 months.

Since the emergence of Covid-19 in the later part of 2019, the ancestral SARS-CoV-2 has undergone several evolutions. This study highlights the necessity of staying updated with the booster dose to offset the waning antibody levels in order to minimize the risk of future breakthrough infections and/or reinfections.

Reference

1. Jeffrey P. Townsend, et al. The durability of natural infection and vaccine-induced immunity against future infection by SARS-CoV-2. Proc Natl Acad Sci U S A. 2022 July 15;119(31):e2204336119. https://doi.org/10.1073/pnas.2204336119.