Immunogenicity after two doses of inactivated virus vaccine in healthcare workers with and without previous COVID‐19 infection: Prospective observational study

Abstract

Vaccines have been seen as the most important solution for ending the coronavirus disease 2019 (COVID‐19) pandemic. The aim of this study is to evaluate the antibody levels after inactivated virus vaccination. We included 148 healthcare workers (74 with prior COVID‐19 infection and 74 with not). They received two doses of inactivated virus vaccine (CoronaVac). Serum samples were prospectively collected three times (Days 0, 28, 56). We measured SARS‐CoV‐2 IgGsp antibodies quantitatively and neutralizing antibodies. After the first dose, antibody responses did not develop in 64.8% of the participants without prior COVID‐19 infection. All participants had developed antibody responses after the second dose. We observed that IgGsp antibody titers elicited by a single vaccine dose in participants with prior COVID‐19 infection were higher than after two doses of vaccine in participants without prior infection (geometric mean titer: 898 and 607 AU/ml). IgGsp antibodies, participants with prior COVID‐19 infection had higher antibody levels as geometric mean titers at all time points (p < 0.001). We also found a positive correlation between IgGsp antibody titers and neutralizing capacity (rs = 0.697, p < 0.001). Although people without prior COVID‐19 infection should complete their vaccination protocol, the adequacy of a single dose of vaccine is still in question for individuals with prior COVID‐19. New methods are needed to measure the duration of protection of vaccines and their effectiveness against variants as the world is vaccinated. We believe quantitative IgGsp values may reflect the neutralization capacity of some vaccines.

An analysis of antibody response following the second dose of CoronaVac and humoral response after booster dose with BNT162b2 or CoronaVac among healthcare workers in Turkey

“…Different results have been reported regarding the relationship between sex and vaccine response. Although a lower antibody response is frequently reported in males receiving the mRNA BNT162b2 15 , 18 or CoronaVac vaccine, 19 no difference was found between the first month antibody levels in males and females, and there was no association between male sex and low antibody levels in this study. In the univariate logistic regression analysis, nurses and other healthcare professionals were in the risk group for low antibody response compared to the physician group, but no difference was found between the occupational groups in the multivariate analysis.…”

“…Chronic diseases may also cause a low response to COVID‐19 vaccines, but the results of inactivated vaccine studies on this subject are quite different from each other. 14 , 19 Differences could be due to the type of chronic diseases in the study groups. Obesity is another issue that affects the response to the vaccine, as shown in this study.…”

“…Neutralizing antibody levels are highly predictive of immune protection from symptomatic coronavirus disease 2019 (COVID- 19) after vaccination, 3 but are technically difficult to use in practice. Instead, immunoglobulin G (IgG) antibodies developed against the receptor-binding domain (RBD) of the spike (S) protein can be used as a predictor in the evaluation of vaccine efficacy.…”

Waning anti-SARS-CoV-2 neutralizing antibody in CoronaVac-vaccinated individuals in Indonesia

“…However, several studies reported that waning NAb titres have been associated with IgG anti-RBD immune response 29,30 and neutralizing capacity was positively correlated with IgG antibody titres. 31 Furthermore, the loss of short-lived plasma cells has been considered the cause of initial rapid waning of antibodies in SARS-CoV-2 infected individuals in general, while establishment of long-lived plasma was thought to contribute to the elevation of antibody level. 32,33 Defective Bcl6+ follicular T-cells due to the absence of germinal centers in the thoracic lymph nodes in dead COVID-19 patients was proposedly unable to activate memory B-cells, leading to a decrease in long-lasting and high-affinity antibody production.…”

A quick scoping review of the first year of vaccination against the COVID-19 pandemic: Do we need more shots or time?

“…Tarke et al, 2022 (USA) [29] Cross Yalçın et al, 2022 (Turkey) [30] Prospective observational study among healthcare workers (n = 148)…”