Waning effectiveness of the third dose of the BNT162b2 mRNA COVID-19 vaccine

Abstract

The duration of protection of the third (booster) dose of the BioNTech/Pfizer BNT162b2 mRNA Coronavirus Disease 2019 vaccine has been the subject of recent investigations, as global discussions around the necessity and effectiveness of a fourth dose are already underway. By conducting a retrospective study implementing a test-negative case-control design, analyzing 546,924 PCR tests performed throughout January 2022 by 389,265 persons who received at least two doses, we find that the effectiveness in each month-since-vaccination decreases significantly. Compared to those vaccinated five months prior to the outcome period, on August 2021, relative protection against infection waned from 53.4% a month after vaccination to 16.5% three months after vaccination. These results suggest that there is a significant waning of vaccine effectiveness against the Omicron variant of the third dose of the BNT162b2 vaccine within a few months after administration. Additional information could assist to comprehensively estimate the effectiveness of the three-dose-strategy.

Estimation of COVID-19 vaccine effectiveness against hospitalisation in individuals aged ≥ 65 years using electronic health registries; a pilot study in four EU/EEA countries, October 2021 to March 2022

“…This may reflect the emergence of Omicron variant. However, it may also represent waning protection soon after the booster dose, as reported by other studies [13,14]. In this respect, VE estimates in our study seemed lower beyond 12 weeks of acquiring booster vaccination status, even though protection remained high (ca 80%) and the distribution of time since the booster was skewed toward the 12-week limit.…”

Immune Response and Clinical Outcomes of BNT162b2 and mRNA1273 Fourth Dose COVID-19 Vaccines; Three Months Follow-up

“…Initially, receipt of the third dose was reported to decrease infection and severe illness rates and to generate a stronger immune response in comparison to that induced by the rst and second doses (12)(13)(14). Yet, shortly after, vaccine effectiveness was reported to wane (15)(16)(17), probably due to the emergence of the highly transmissible Omicron VOC (18-20), as well as waning of the immune response (21). This raised the question of whether a fourth vaccine dose was needed.…”

Slow waning of antibodies following a third dose of BNT162b2 in adults who had previously received two doses of inactivated vaccine

“…Third doses have been particularly important for improving protection against variants. However, waning clinical protection particularly against Omicron was noted after receipt of third doses [4, 5], with fourth doses then providing additional protection [6, 7].…”