The COVID-19 situation in early 2023, more than three years after the start of the pandemic, has changed significantly. Globally, population-level immunity has increased significantly, due to substantial and increasing vaccine use along with infection-induced immunity, or the combination of both (hybrid immunity). Most countries have lifted most or all public health and social measures, and while the SARS-CoV-2 virus continues to circulate, the third year of the COVID-19 pandemic has been marked by significant reduction in rates of hospitalization, admission to ICU and deaths across all age groups. This is due to a number of factors including increasing population level immunity from infection and/or vaccination, and earlier testing and access to COVID-19 therapeutics. Nonetheless, certain subgroups continue to be at greater risk of severe disease and mortality and account for most of the ongoing COVID-19-related mortality; thus, even a minor decrease in vaccine effectiveness with time in vulnerable subgroups translates into a rise in cases of severe disease and death.
This Roadmap addresses the evolving public health needs at the present time with Omicron and its sublineages dominating circulation globally and in the context of high population-level immunity, using a base case scenario that assumes that the virus will continue to evolve but cause less severe disease with possible surge in infections that will require periodic booster doses of the vaccine to protect the high priority groups. Consideration has been given to high population immunity, ample vaccine supply, declining risk of mortality and severe disease, global dominance of Omicron and its subvariants, differential vaccine performance against infection and severe disease outcomes, and post COVID-19 conditions.
Based on an extensive evidence review including systematic reviews and meta-analyses, the Roadmap provides updates on new priority-use groupings (reducing from four to three strata); specific recommendations for primary series and boosters according to priority-use groups; variant-containing vaccines; heterologous schedules; and vaccination during pregnancy. Specifically, this Roadmap suggests:
• Longer interval for additional boosters (i.e. beyond the first booster) for high priority-use groups;
• Medium risk groups are no longer routinely recommended for additional boosters beyond the first booster;
• Additional booster dose during pregnancy if last dose was given more than 6 months ago; ideally to be given by mid-second trimester;
• Additional booster dose for frontline health workers 12 months after the last dose;
• Primary series in healthy children and adolescents could be considered, based on country context such as disease burden in this age group, cost effectiveness, other health or programmatic priorities and opportunity costs;
- Position paper