Current evidence on efficacy of COVID‐19 booster dose vaccination against the Omicron variant: A systematic review

Abstract

Coronavirus disease 2019 (COVID‐19) is an ongoing pandemic, which affected around 45 million confirmed cases of COVID‐19, including more than 6 million deaths. However, on November 24, 2021, the World Health Organization announced a new severe acute respiratory syndrome coronavirus 2 variant designated as the B.1.1.529, a variant of concern (VOC), and the variant has been named as “Omicron.” Available preliminary evidence suggests that, as compared with previous VOCs, it has an increased risk of infectivity. Studies have shown that protection from various vaccines effectiveness against hospitalization and death from severe COVID‐19 disease is decreasing slowly after a two‐dose schedule of COVID‐19 vaccines. In response to experiencing a new COVID‐19 variant and ongoing resurgence of cases, the importance of COVID‐19 vaccine booster dose and durability of the effect of the third dose of vaccine against COVID‐19 Omicron variant is controversial yet. To address this, we conducted a systematic literature survey on effectiveness of the third or booster dose of COVID‐19 vaccine against the Omicron variant. We have performed a systematic search in PubMed (Medline), Google Scholar, and MedRXiv database, from inception to January 2022 using the MeSH terms and keywords “Corona Virus Disease‐2019 OR COVID‐19 AND Omicron AND COVID‐19 Booster Vaccine.” We have identified a total of 27 published studies. We have reviewed all the eligible available studies on the effectiveness of the COVID‐19 vaccine booster shots against the Omicron variant. This review may be helpful in accelerating the COVID‐19 booster dose vaccination.

T‐cell responses to SARS‐CoV‐2 Omicron spike epitopes with mutations after the third booster dose of an inactivated vaccine

“…Encouragingly, as the vast majority of T cell epitopes are fully conserved, ancestral SARS‐CoV‐2‐specific T cells are expected to cross‐recognize the Omicron variant, which has been shown by our data and several recent works 13–16 . Previous studies reported that a third vaccine dose showed a satisfactory safety profile and induced a stronger immune response to SARS‐CoV‐2 and variants of concern 26–29 . Our study provides further evidence that after two doses of an inactivated vaccine, a third booster vaccination substantially enhanced T‐cell responses to the spike proteins of both the ancestral strain and the Omicron variant, although the enhancement was slightly weakened by Omicron mutations, especially G339D and N440K.…”

“… 13 , 14 , 15 , 16 Previous studies reported that a third vaccine dose showed a satisfactory safety profile and induced a stronger immune response to SARS‐CoV‐2 and variants of concern. 26 , 27 , 28 , 29 Our study provides further evidence that after two doses of an inactivated vaccine, a third booster vaccination substantially enhanced T‐cell responses to the spike proteins of both the ancestral strain and the Omicron variant, although the enhancement was slightly weakened by Omicron mutations, especially G339D and N440K.…”

COVID-19 infection, and reinfection, and vaccine effectiveness against symptomatic infection among health care workers in the setting of omicron variant transmission in New Delhi, India

“… 22 , 23 , 24 Studies have also reported waning effect of vaccines with passage of time. 25 The booster dose helped in increasing the effect against the variant, though that also reduced with increasing time. 26 In a study from England, no effect was seen against omicron after 5 months of two doses of AZD-1222 vaccine (AstraZeneca) and other vaccines also.…”

Health Beliefs and Socioeconomic Determinants of COVID-19 Booster Vaccine Acceptance: An Indonesian Cross-Sectional Study

“…Other than the increased accessibility of COVID-19 tests, this pattern can be attributed to the much higher COVID-19 vaccine coverage at this time [ 2 , 3 ]. At the beginning of the Omicron wave, around 50% of the world population had been fully vaccinated, compared to 6% at the beginning of the Delta wave [ 4 , 5 ].…”