Waning Immunity after the BNT162b2 Vaccine in Israel

Abstract

Background In December 2020, Israel began a mass vaccination campaign against coronavirus disease 2019 (Covid-19) by administering the BNT162b2 vaccine, which led to a sharp curtailing of the outbreak. After a period with almost no cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, a resurgent Covid-19 outbreak began in mid-June 2021. Possible reasons for the resurgence were reduced vaccine effectiveness against the delta (B.1.617.2) variant and waning immunity. The extent of waning immunity of the vaccine against the delta variant in Israel is unclear. Methods We used data on confirmed infection and severe disease collected from an Israeli national database for the period of July 11 to 31, 2021, for all Israeli residents who had been fully vaccinated before June 2021. We used a Poisson regression model to compare rates of confirmed SARS-CoV-2 infection and severe Covid-19 among persons vaccinated during different time periods, with stratification according to age group and with adjustment for possible confounding factors. Results Among persons 60 years of age or older, the rate of infection in the July 11–31 period was higher among persons who became fully vaccinated in January 2021 (when they were first eligible) than among those fully vaccinated 2 months later, in March (rate ratio, 1.6; 95% confidence interval [CI], 1.3 to 2.0). Among persons 40 to 59 years of age, the rate ratio for infection among those fully vaccinated in February (when they were first eligible), as compared with 2 months later, in April, was 1.7 (95% CI, 1.4 to 2.1). Among persons 16 to 39 years of age, the rate ratio for infection among those fully vaccinated in March (when they were first eligible), as compared with 2 months later, in May, was 1.6 (95% CI, 1.3 to 2.0). The rate ratio for severe disease among persons fully vaccinated in the month when they were first eligible, as compared with those fully vaccinated in March, was 1.8 (95% CI, 1.1 to 2.9) among persons 60 years of age or older and 2.2 (95% CI, 0.6 to 7.7) among those 40 to 59 years of age; owing to small numbers, the rate ratio could not be calculated among persons 16 to 39 years of age. Conclusions These findings indicate that immunity against the delta variant of SARS-CoV-2 waned in all age groups a few months after receipt of the second dose of vaccine.

Alpha (B.1.1.7) and Delta (B.1.617.2 – AY.40) SARS-CoV-2 variants present strong neutralization decay at M4 post-vaccination and a faster replication rates than D614G (B.1) lineage

“…We read with interest the article by Dimeglio et al 1 , showing the importance of the SARS-CoV-2 anti-S antibody response. Along with previous results showing a strong decrease of antibody and neutralization titers after vaccination 2,3 , especially for Gamma variant, their results highlight the usefulness of assessing antibody levels among HealthCare Workers (HCWs) and to monitor the effects of emerging SARS-CoV-2 variants. Likewise, the article by Douxfils et al 4 , demonstrated post-vaccination decreasing neutralizing antibodies titers and highlighted the difficulty to obtain a definite protection threshold., They also could not verified the effects of Alpha and Delta variants.…”

“…Likewise, the article by Douxfils et al 4 , demonstrated post-vaccination decreasing neutralizing antibodies titers and highlighted the difficulty to obtain a definite protection threshold., They also could not verified the effects of Alpha and Delta variants. Recently, Goldberg et al 3 assessed Delta breakthrough infections among a large vaccinated population and demonstrated a decreasing protection in all age groups a few months after receiving a full vaccination scheme. To date, little data are still available regarding comparative neutralizing capability of antibodies against Alpha and Delta variants several months after vaccination schemes.…”

COVID Booster Shots: The Need of the Hour

“…Reasons could be multifaceted, from ever-changing/mutating virus, the waning of vaccine efficacy, and daily medications for other co-morbid conditions, including autoimmune diseases. Multiple studies in USA and Israel have shown that vaccine efficacy decreases over time [3][4][5][6]. Breakthrough COVID infections match the timing of about six months after the first group of high-risk workers and the elderly were vaccinated against SARS-CoV-2.…”

“…Though this study did not study the waning of vaccine efficacy, further research on this possibility is warranted as both mRNA vaccines were very effective against COVID early after vaccine administration, and effectiveness reduced significantly with time. It is essential to note an early study from Israel that did study the rate of infection in patients who previously received two doses of the Pfizer-BioNTech vaccine for SARS-CoV-2: immunity waned in all age groups [4]. This case report showcases fully vaccinated patients who were hospitalized for severe COVID-19.…”

Primary COVID-19 vaccine cycle and booster doses efficacy: analysis of Italian nationwide vaccination campaign

“…3 Despite the efficacy of COVID-19 vaccines is now straightforward and unquestionable, even higher than that of vaccines used for preventing other respiratory infectious diseases such as Influenza, 4 waning immunity against SARS-CoV-2 has been widely reported, especially 4 to 6 months after completing the primary COVID-19 vaccination cycle, 5 so that there is ongoing debate as to whether additional vaccine booster doses may be necessary to restore the immune response to levels similar to or even greater than those achievable immediately after completing a primary COVID-19 vaccination. 5 This article is hence aimed at providing an updated analysis of primary COVID-19 vaccination and vaccine booster doses efficacy by analyzing data emerging from the ongoing Italian nationwide COVID-19 vaccination campaign.…”