United States: For ten years, Americans have had access to flu shots that protect against four strains of the virus: two A strains and two B strains, so as to augment the genetic diversity in their program.
This fall, nevertheless, all the flu shots to be distributed in the United States are bound to be composed of only three strains, as the COVID-19 pandemic has called for such a change.
One Flu strain is extinct owing to COVID
In 2020, all the precautions that helped people avoid Covid had an unexpected benefit: One of the major lineages of the flu family, known as the B strain, and is called the Yamagata clada by geneticists, has become extinct genetically, and not a single case of Yamagata clade has been reported ever since.
The World Health Organization (WHO), in September said that “inclusion of the Yamagata-lineage antigens in influenza vaccines is no longer warranted,” as CNN Health reported.
Moreover, in October, the US Food and Drug Administration (FDA) also advised the health experts to drop off Yamagata strains as early as possible.
During the 1990s, when Yamagata strain was flourishing, another branch of B-strain flu viruses, called Victoria, appeared rather uncommon, but it re-emerged in the 2000s.
In the 1990s, when Yamagata was in its heyday, another branch of B-strain flu viruses called Victoria was seen only sporadically in testing, but it had a resurgence in the 2000s.
Therefore, health experts were facing a quandary about whether to drop off the strain or not.
Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia and a member of the FDA’s Vaccines and Biological Products Advisory Committee, or VRBPAC, said, “We’ve been talking about this for four years,” as CNN Health reported.
The next step to discuss by the committee
On Tuesday, the committee is expected to have a discussion on next steps and vote on the recommendations regarding flu vaccine for the fall.
Offit stated that he believes that all the flu vaccines to be released in the US this fall would be three-strain – ones where there would be two A strains and one B/Victoria but no B/Yamagata strains. This is in accordance with the recommendations of the WHO as well as the VRBPAC committee.
Moreover, Offit added that there are several good reasons for dropping the Yamagata strain, and “You don’t want to be vaccinating people for something they don’t need,” reported CNN Health.
A few concerns are shared by the experts
According to Dr. Jodie Guest, senior vice chair of the Department of Epidemiology at Emory University’s Rollins School of Public Health – there is the possibility that few harms could be felt if the strain is continued to include.
She added, “Anytime these flu vaccines are being produced, they are – depending on which vaccines you are talking about – using live or attenuated virus, and you do have to grow it.”
And, “So while it would be an anticipated, incredibly small risk, there is the possibility you could reintroduce it into the population by having it contained in a vaccine,” as CNN Health reported.
What other experts have to say about the move?
Other scientists have mentioned that it would be beneficial to discontinue Yamagata strain due to the fact that free up of resources is going to increase the amount of doses for the global vaccination campaigns.
In an article released by the FDA on the same day, Dr. Arnold Monto, one of the FDA’s vaccine advisers, Dr. Maria Zambon, UK Health Security Agency, and the FDA’s Dr. Jerry Weir, said the move would open new doors concerning new vaccine formulas.
According to CNN Health reports, since the shot’s B/Victoria and A/H1N1 strains are more effective than the A/H3N2 component, experts advise doubling the dose of H3N2 or adding a second family of the line of this strain.
However, as the authors observe, this process would need to go through the trials and regulatory approval, so don’t expect threemade flu shots to be a thing in the foreseeable future.
Instead, as per them, it would be “more of a long-term goal for improving vaccine effectiveness.”