Last week, the COVID vaccine composition advisory group of the World Health Organisation (WHO) convened to address the recent developments in SARS-CoV-2 and their implications for the vaccine. They issued a recommendation for vaccine manufacturers to discontinue the use of the ancestral (original) strain and instead adopt a monovalent (single-strain) vaccine formulation, specifically incorporating a descendant lineage called XBB.1, such as XBB.1.5.
Why a more robust and effective approach is required to combat XBB lineages
The World Health Organisation (WHO) laid emphasis on the fact that the currently authorised COVID-19 vaccines, including those developed based on the original virus strain, still offer significant protection against severe illness and mortality.
They observed that XBB descendant lineages, such as XBB.1.5 and XBB.1.16, exhibit significant immune evasion, with XBB.1.5 being among the variants demonstrating the most substantial resistance to neutralising antibodies. Nevertheless, they acknowledged that the estimation of vaccine efficacy (VE) against prevailing strains is constrained, as some studies indicate VE comparable to BA.5, while others indicate decreased VE against XBB.1 lineages.
Investigations involving blood samples from individuals who received two to four doses of mRNA vaccines exhibited significantly diminished neutralisation effectiveness against XBB.1 lineages. However, individuals with hybrid immunity, resulting from both prior infection and vaccination, demonstrated elevated antibody titers against XBB.1 viruses.
Future COVID-19 vaccines
The advisory group also stated that considering the prevailing dominance of XBB.1 lineage viruses, the objective of developing new COVID formulations should be to effectively neutralise XBB-descendant lineages. They specifically mentioned the inclusion of XBB.1.5 as an example but also suggested that XBB.1.16 could serve as an alternative, given the minimal genetic and antigenic distinctions between the two.
But, why do we need a new monovalent COVID-19 vaccine again?
WHO’s research indicated multiple reasons such as:
- The original virus strain is no longer circulating in people
- It prompts very low levels of antibodies against current strains
- It reduces the concentration of the new target antigen
It’s important to note that the future of COVID vaccines will depend on ongoing research, regulatory approvals, global collaborations, and the evolving nature of the virus. Continued monitoring, adaptation, and innovation will shape the path forward in the fight against COVID-19.
In the meantime, it’s our personal responsibility to stay up to day with our vaccination status. All adults can get a booster if it’s been 6 months or more since their last COVID-19 vaccine or confirmed COVID-19 infection – whichever was most recent.
Heathershaw’s vaccination clinic is open with appointments available each week.
As COVID-19 and flu vaccines can be co-administered, joint appointments for flu and COVID-19 boosters vaccines are also available during some of our sessions (see our website to identify which sessions allow for joint immunisation).
Also, book now online if you haven’t received your annual flu vaccination already.
Opinions or facts expressed within the content have been sourced from various news sources. While every effort has been taken to source them accurately, the pharmacy, its owners, staff or other affiliates do not take any responsibility for errors in these sources. Patients should not rely on the facts or opinions in the content to manage their own health, and should seek the advice of an appropriate medical professional. Further, the opinions or facts in the content do not reflect the opinions and beliefs of the pharmacy, its owners, staff or other affiliates.
