Does the time between SARS-CoV-2 infection and vaccination affect immunity?

In a recent study posted on medrex sib*Preprint server, Oregon Health and Science University researchers evaluated the impact of the period between coronavirus disease 2019 (COVID-19) infection and vaccination on immunity to infection.

As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread, long-term immunity against COVID-19 becomes more important. Global public health concerns are exacerbated by the continued emergence of new SARS-CoV-2 variants that are more contagious and contagious than previous variants. Extensive investigation is needed to understand different aspects of SARS-CoV-2 immunity, especially the temporal profile between infection and repeated vaccinations.

study: Time from vaccination to infection affects immunity to SARS-CoV-2 variantsImage Credit: Ja_inter / Shutterstock

About research

In the current study, researchers evaluated the combined effects of COVID-19 infection and vaccination or hybrid immunity and their relative timing on the amount and quality of antibodies induced.

The team recruited 10 people who tested positive for COVID-19 by polymerase chain reaction (PCR) prior to vaccination from December 2020 to March 2021. Blood samples were taken before and after two doses of BNT162b2 vaccination. Additionally, 20 sex- and age-matched individuals with no previous self-reported history of COVID-19 infection were recruited and blood samples were collected before and after vaccination. In addition, we estimated serum neutralization titers and compared these two cohorts of hers via a live viral focus reduction neutralization test (FRNT).

An additional cohort was recruited, including 23 vaccinated individuals who demonstrated and did not demonstrate hybrid immunity due to previous COVID-19 infection and 23 subjects with vaccine breakthrough infections . Serological samples were obtained within 60 days of either vaccination or PCR-confirmed breakthrough infection. Additionally, the team estimated spike-specific antibody levels in this cohort via enzyme-linked immunosorbent assay (ELISA).

The hybrid immune group included subjects diagnosed with SARS-CoV-2 infection approximately 40–404 days after vaccination and subjects vaccinated 35–283 days after COVID-19 diagnosis . The team used age, sex, exposure interval, and elapsed time between last exposure and sample collection to characterize the association between neutralizing titers and antibody levels. The cohort was further divided into he 100-day exposure interval bins.

result

The study results found elevated serum neutralization titers in previously infected and naïve cohorts before and after COVID-19 vaccination. Also, previously infected individuals compared to those vaccinated against all strains, including the original SARS-CoV-2 (WA1) and variants such as the alpha, beta and gamma variants (VOCs) of concern. Titers were significantly higher among individuals with a history of This indicates that hybrid immunity resulting from both natural infection and vaccination can lead to elevated neutralizing serum antibody titers.

ELISAs performed in larger cohorts antigenThe percentage of specific antibodies was 3.6-fold higher with hybrid immunization than with vaccination alone. A class-specific ELISA revealed that this phenomenon was due to a 3.7-fold increase in immunoglobulin (Ig)-G levels and his 3.2-fold increase in IgA levels. IgM levels showed no such variation between the two groups. Hybrid immunization against the SARS-CoV-2 spike protein also increased total antibody levels by 3.1-fold.

The team also Neutralizing antibody Titers against SARS-CoV-2 and all tested variants were increased in the group with hybrid immunity compared with the cohorts that received only vaccination. Neutralization titers increased 8.4-fold, 12.5-fold, 22.7-fold, 9.6-fold, 19-fold, and 13.3-fold against WA1, alpha, beta, delta, Omicron BA.1, and Omicron BA.2, respectively . The highest increases were recorded for the BA.1 and BA.2 subvariants of beta and omicron.

In the hybrid-immune group, neutralizing antibody titers and antibody levels were particularly associated with exposure intervals. The most significant correlations were observed between SARS-CoV-2 spike-specific antibody levels and WA1, alpha, delta, beta, and omicron BA.1 and BA.2 neutralization. Additionally, the range of altitudes noted by the team varied between subspecies. By 400 days, neutralization titers were 5.3-fold against WA1, 4.8-fold against alpha, 11.5-fold against beta, 11.2-fold against delta, 17.6-fold against Omicron BA.1, Omicron BA 14.3 times higher than .1. 2. Neutralization titers were 4.2-fold higher against WA1, 4.1-fold higher against alpha, 9.6-fold higher 7.1-fold over Omicron BA.1 and 12.5-fold over Omicron BA.1. -fold, Omicron BA.2 is 10.7 times.

Conclusion

The results of this study showed that individuals with hybrid immunity exhibited strong SARS-CoV-2 neutralizing antibody responses against all variants, including the SARS-CoV-2 Omicron BA.2 sublineage. The team also found that increasing the time interval between vaccination and infection, up to 400 days, significantly improved neutralization titers. These findings suggest that anti-SARS-CoV-2 antibody responses mature continuously for a minimum of 400 days after the last exposure to the antigen after initial exposure to the virus through infection or vaccination. . The researchers believe these findings may extend to the dose of his COVID-19 booster vaccine, given at longer intervals that could elicit greater protection against infection.

*Important Notices

medrex sib We publish a non-peer-reviewed, preliminary scientific report and should not be taken as conclusive, to guide clinical practice/health-related actions, or to be treated as established information.