Although it may seem unbelievable, one good thing has come out of the Covid-19 pandemic. The measures taken during the coronavirus health crisis – restrictions, social distancing, masks, hand hygiene… – have achieved unprecedented results. And, thanks to this, strains of influenza were eliminated for the first time.
This is known as Yamagata Prefecture, and according to the World Health Organization (WHO), no cases have been detected since March 2020.It is for this reason that this organism Proposal to change vaccine ingredients for next season2024-25, does not include it.
Each year, the World Health Organization releases recommendations for the ingredients in next season’s influenza vaccine (February in Northern Hemisphere August or September for the Southern Hemisphere). These recommendations are based on multiple sources of information: influenza epidemiological surveillance, antigenic and genetic characteristics of detected viruses, serological studies, vaccine effectiveness data, antiviral drug resistance, etc.
So this year, after deliberation by an expert group convened by the World Health Organization, recommendations on the ingredients of the northern hemisphere influenza vaccine for the 2024-25 season have been announced. It is recommended that trivalent vaccines be used first, regardless of the Yamagata lineage component of influenza B viruses.
Does this mean the Yamagata flu strain is extinct? As we speak, the World Health Organization has not confirmed the detection of influenza viruses of this lineage since March 2020. There have been recent reports that the test results have not been confirmed or identified as a live attenuated vaccine virus.
“Although It is uncertain whether lineage B/Yamagata viruses are extinct; they are unlikely to cause outbreaks. next season. On the other hand, there is a theoretical risk of transmission associated with the use of this virus in the production of inactivated or attenuated vaccines, which is why the World Health Organization recommends excluding this strain from vaccines in use as soon as possible. They said from the Spanish Association of Vaccinology (AEV).
this Decision by the World Health Organization and supported by the U.S. Drug Administration (FDA) Last week, the expert panel advising her on the vaccine unanimously voted to recommend a three-strain flu vaccine that would rule out any B viruses to which Yamagata Prefecture belongs, a big bet facing huge public health difficulties and challenges.
not that easy
because Changing the way flu vaccines are produced won’t be easy or quick, these changes require regulatory review and approval. On the other hand, this is a decision with associated difficulties and very serious implications that must be considered.
In fact, in September 2023, the World Health Organization again recommended the use of trivalent vaccines (excluding the Yamagata influenza B component) in its recommendations for the 2024 influenza season in the southern hemisphere. Vaccine makers say they may have problems adjusting production systems in a timely manner Meets regulatory requirements for new trivalent vaccines. These will come from the production of the vaccine as they have to restart the vaccine manufacturing process which has almost stopped production,
But they are not the only problem, regulators are also faced with the problem, “which must evaluate and, where appropriate, approve new products. For public health authorities, on the one hand, they must decide on their own specific circumstances to return to priority or exclusivity.” The pace of use of trivalent vaccines, on the other hand, Weighing the risks of keeping Yamagata bloodline flowing during the production of inactivated vaccines, especially in the quadrivalent vaccine that continues to be administered,” they noted in AEV.