Long-term effects of previous SARS-CoV-2 infection on immune response after COVID-19 vaccination

Despite evidence of current crop efficacy of the vaccine used against coronavirus disease 2019 (COVID-19) in clinical trials and post-marketing surveillance data Effectiveness In the real world, it is influenced by various factors: population demographics, circulating mutations in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), time elapsed since vaccination, and vaccination protocols. increase.

Due to the increased risk of breakthrough infections, a third (booster) vaccination is currently underway. Vaccination after SARS-CoV-2 infection seems to be the norm, as more and more people are infected.

Responses to the vaccine have been positively affected by previous SARS-CoV-2 infections. However, the long-term implications remain unclear. Therefore, in actual evidence studies, it is important to examine the duration of the immune response to the vaccine-induced response and the long-term effects of SARS-CoV-2 infection prior to vaccination.

the study

Research published in Clinical and translational immunology The aim was to determine the effect of previous infections with SARS-CoV-2 infection on the immune response after long-term COVID-19 vaccination.

Blood samples were collected longitudinally from a community (COVID-19 immunology) study to determine binding (WHO BAU mL-1) and neutralizing antibody titers to 10 SARS-CoV-2 mutants over 7 months. .. All samples received BNT162b2 (Comirnaty, Pfizer-BioNTech) to 118 SARS-CoV-2 recovery and 289 SARS-CoV-2 inexperienced healthcare workers previously exposed to SARS-CoV-2. It was collected later.

In addition, another group of people (47 before and 60 before SARS-CoV-2 infection) was followed for 3 months after receiving the ChAdOx1 nCoV-19 vaccine (Vaxzevria, AstraZeneca). T cells SARS-CoV-2 specific responses were studied in these vaccine recipients recovered with SARS-CoV-2-naive or SARS-CoV-2.

result

This study reported a marked increase in both humoral and cell-mediated immune responses to vaccination after previous SARS-CoV-2 infection. It has also been reported that the neutralization efficacy and scope of application for SARS-CoV-2 mutants are higher than those of individuals who were SARS-CoV-2 naive.

Significant reductions in BAUmL1 and pseudoneutralizing antibody titers were recorded during the first month after vaccination with ChAdOx1 nCoV-19 and BNT162b2. Compared to BNT162b2, immunization with ChAdOx1 nCoV-19 showed significantly lower titers. These findings support the recommendations for booster immunization and the plans for the SARS-CoV-2 vaccine program.

As previously reported, T cells among medical personnel suffering from almost mild SARS-CoV-2 infection prior to vaccination, 3 months after ChAdOx1 nCoV-19 and 7 months after BNT162b2. It was further demonstrated that the response and antibody titers remained significantly increased. This indicates that the effects of previous infections on the immune response after vaccination are not temporary. The memory compartment appears to be constantly evolving after both infection and vaccination, but the widespread immunity increase after vaccination appears to be small.

In addition, vaccinated individuals who recovered from SARS-CoV-2 showed a higher development of neutralizing antibody response to the SARS-CoV-2 variant. This finding suggests that SARS-CoV-2 recovered immunocompetents elicit a better cellular response than SARS-CoV-2 inexperienced vaccinated.

The results show that a decrease in antibody titer in some individuals 3-7 months after the second dose of COVID-19 vaccine requires a third booster immunization in a small proportion of the vaccinated population. It shows that. Notably, these assessments are performed during the alpha variant and these titers may result in lower efficacy for the delta variant.

Significant differences were observed between 3-4 and 6-8 weeks for pseudoneutralization in SARS-CoV-2 inexperienced participants. This suggested improved memory formation in the latter group. We also found that longer periods between SARS-CoV-2 infection and COVID-19 vaccination increased neutralization efficacy and immune range.

Further research is needed to assess the potential differences in immunological memory lifespan. This study was observable and single-centered, with limitations as most women included only health workers of working age. Antibody trajectories may vary in the elderly and in environments without repeated encounters with the virus.

Conclusion

Here, the potential for enhanced cell-mediated immune response, antibody titers, and neutralization coverage of vaccinated individuals with previous SARS-CoV-2 infection, vaccinated individuals without previous SARS-CoV-2 infection. Compared with. The results revealed that previous infections emphasized these effects after vaccination.

Therefore, previous SARS-CoV-2 infections should be kept in mind when developing vaccination policies, planning booster immunodoses, and designing COVID-19 vaccination programs, both now and in the future. I have.