Waning Immune Humoral Response to BNT162b2 Covid-19 Vaccine over 6 Months

Abstract

Background Despite high vaccine coverage and effectiveness, the incidence of symptomatic infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been increasing in Israel. Whether the increasing incidence of infection is due to waning immunity after the receipt of two doses of the BNT162b2 vaccine is unclear. Methods We conducted a 6-month longitudinal prospective study involving vaccinated health care workers who were tested monthly for the presence of anti-spike IgG and neutralizing antibodies. Linear mixed models were used to assess the dynamics of antibody levels and to determine predictors of antibody levels at 6 months. Results The study included 4868 participants, with 3808 being included in the linear mixed-model analyses. The level of IgG antibodies decreased at a consistent rate, whereas the neutralizing antibody level decreased rapidly for the first 3 months with a relatively slow decrease thereafter. Although IgG antibody levels were highly correlated with neutralizing antibody titers (Spearman’s rank correlation between 0.68 and 0.75), the regression relationship between the IgG and neutralizing antibody levels depended on the time since receipt of the second vaccine dose. Six months after receipt of the second dose, neutralizing antibody titers were substantially lower among men than among women (ratio of means, 0.64; 95% confidence interval [CI], 0.55 to 0.75), lower among persons 65 years of age or older than among those 18 to less than 45 years of age (ratio of means, 0.58; 95% CI, 0.48 to 0.70), and lower among participants with immunosuppression than among those without immunosuppression (ratio of means, 0.30; 95% CI, 0.20 to 0.46). Conclusions Six months after receipt of the second dose of the BNT162b2 vaccine, humoral response was substantially decreased, especially among men, among persons 65 years of age or older, and among persons with immunosuppression.

Vaccine-induced humoral and cellular immunity against SARS-CoV-2 at 6 months post BNT162b2 vaccination

“…There seemed no difference between cellular immunity conferred by natural infection and the reduction in cellular immunity by vaccines. It has been previously reported that the antibody titer is negatively correlated with age up to 6 months after vaccination [9], but SP-specific T-cell response has not been related to age [10]. In our study, there was no correlation among age, gender, BMI, alcohol, or smoking.…”

Epidemic Surveillance Models for Containing the Spread of SARS-CoV-2 Variants: Taiwan Experience

“…Although the scale of case number in Y axis in supplementary figure 7 As far as the results of external prediction are concerned, there were three weeks between 9 August and 29 August 2020 in which the observed numbers of domestic cases were beyond the upper limit of surveillance level. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) Southern (42), Waitematā (38), Auckland (34), Canterbury (34), Waikato (26)…”

Boosters appear effective, but are they always needed?

“… 8 Other reports from Israel and Qatar indicate speedily declining protection. 2 , 3 Although these reports strengthen the case for a booster dose of BNT162b2, there is no evidence yet to suggest that global policies related to other vaccines should be influenced by this experience.…”

“…Currently approved vaccines provide high levels of protection against serious illness, but do not confer mucosal immunity to resist entry of the virus into the respiratory tract. When mostly mild breakthrough infections were reported from different countries, 1 , 2 , 3 concern arose that individuals with a fast fading immune response to the standard vaccination schedule might experience serious illness if infected. 1…”