Expert review of global real-world data on COVID-19 vaccine booster effectiveness and safety during the omicron-dominant phase of the pandemic

Abstract

Introduction: COVID-19 vaccines have been highly effective in reducing morbidity and mortality during the pandemic. However, the emergence of the Omicron variant and subvariants as the globally dominant strains have raised doubts about the effectiveness of currently available vaccines and prompted debate about potential future vaccination strategies. Areas covered: Using the publicly available IVAC VIEW-hub platform, we reviewed 52 studies on vaccine effectiveness (VE) after booster vaccinations. VE were reported for SARS-CoV-2 symptomatic infection, severe disease and death and stratified by vaccine schedule and age. In addition, a nonsystematic literature review of safety was performed to identify single or multi-country studies investigating adverse event rates for at least two of the currently available COVID-19 vaccines. Expert opinion: Booster shots of the current COVID-19 vaccines provide consistently high protection against Omicron-related severe disease and death. Additionally, this protection appears to be conserved for at least 3 months, with a small but significant waning after that. The positive risk-benefit ratio of these vaccines is well established, giving us confidence to administer additional doses as required. Future vaccination strategies will likely include a combination of schedules based on risk profile, as overly frequent boosting may be neither beneficial nor sustainable for the general population.

Waning vaccine response to severe COVID-19 outcomes during omicron predominance in Thailand

“…Our study found that the three vaccine types used for boosting in Thailand, P zer-BioNTech, Moderna and ChAdOx1 nCoV-19, offered similar protection against severe COVID-19 outcomes. Comparable protection from ChAdOx1 nCoV-19 and P zer-BioNTech against infection, hospitalization, ICU admissions and deaths, has been previously reported [12,20,22,23]. Our ndings corroborate this evidence and supports the use of mRNA vaccines and viral vector vaccines as booster vaccines, providing much needed exibility to incorporate different vaccines into schedules according to local supply and logistical considerations.…”

Safety and immunogenicity of SII-NVX-CoV2373 (COVID-19 vaccine) in adults in a phase 2/3, observer-blind, randomised, controlled study

“…reported that the real-world evidence from different COVID-19 vaccines (parent strain) supports the completion of primary series and booster vaccinations where appropriate, especially to restore waning vaccine effectiveness against the more infectious Omicron variant and protect populations from severe outcomes, hospital admissions, and longer lasting post-COVID-19 complications, as well as mortality. 12 Considering this, booster doses are recommended at about 4–6 months or later after completion of primary immunization.…”

Waning vaccine response to severe COVID-19 outcomes during omicron predominance in Thailand

“…Our study found that the three vaccine types used for boosting in Thailand, Pfizer-BioNTech, Moderna and ChAdOx1 nCoV-19, offered similar protection against severe COVID-19 outcomes. Comparable protection from ChAdOx1 nCoV-19 and Pfizer-BioNTech against infection, hospitalization, ICU admissions and deaths, has been previously reported [ 12 , 20 , 23 , 24 ]. Our findings corroborate this evidence and supports the use of mRNA vaccines and viral vector vaccines as booster vaccines, providing much needed flexibility to incorporate different vaccines into schedules according to local supply and logistical considerations.…”