Good practice statement on the use of variant-containing COVID-19 … – ReliefWeb

This Good Practice Statement on the use of variant-containing COVID-19 vaccines was updated on the basis of advice by the Strategic Advisory Group of Experts (SAGE) on Immunization at its meeting on 28 September 2023.

In May 2023, the Technical Advisory Group on COVID-19 Vaccine Composition (TAG-CO-VAC) recommended moving away from including the ancestral strain in future COVID-19 vaccine formulations. The reasons for adopting a monovalent variant-containing approach to target current and emerging variants can be found here.

The updated recommendations made by TAG-CO-VAC and this Good Practice Statement synthesize current evidence on variant-containing COVID-19 vaccines, notably those containing XBB. This document contains some off-label recommendationsa .

In this document, the terms primary series and initial doses are used interchangeably, and so are the terms additional doses and booster doses.

Background and methods

Globally, population-level immunity against SARS-CoV-2 has increased substantially due to widespread COVID-19 vaccine-derived immunity, SARS-CoV-2 infection-derived immunity, or a combination of both (hybrid immunity). Meanwhile, significant reductions in severe disease and death related to SARS-CoV-2 have been observed across all age groups. As such, most countries have lifted many or all of their public health measures.

In the fourth year of the pandemic, new SARS-CoV-2 subvariants continue to circulate globally, leaving vulnerable populations at continued risk of severe SARS-CoV-2 disease and death. The spike protein of SARSCoV-2 continues to diverge from the ancestral strain.

After Omicron emerged in November 2021, earlier variants (Alpha, Beta, Gamma, and Delta) disappeared from humans. By May 2023, global prevalence was dominated by Omicron subvariants including XBB.1.5, XBB.1.16 and XBB.1.9. More recently, additional Omicron subvariants have emerged, such as EG.5 and BA.2.86.

While Omicron and its subvariants have led to less severe disease than the ancestral strain, there have been surges in hospitalization and death in vulnerable populations due to elevated community transmission and periodic waves of infections.

WHO conducted a rapid review of current evidence on XBB variants and monovalent XBB vaccines retrieved from scientific publications, preprints, and data provided by manufacturers (1-3). The following topics were reviewed:

immune evasion in humans;

variant-adapted vaccines: humoral and cell-mediated immune responses following vaccination and/or infection in humans and animals;

vaccine effectiveness; and

vaccine safety.

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Good practice statement on the use of variant-containing COVID-19 ... - ReliefWeb