COVID-19 pandemic limitations effectively ended the 2020-2021 flu season, with influenza cases in the United States reaching never-before-seen lows. Because there was so little virus going around, some scientists believe one of the primary types of influenza may have gone extinct due to a shortage of persons to infect. An Australian study team recently revealed in the journal Nature Reviews that influenza B/Yamagata is one of four strains typically included in annual flu vaccines, but that virus appears to have dropped totally off the radar in the midst of COVID lockdowns. Since March 2020, when COVID lockdowns effectively terminated the 2019-2020 flu season, no B/Yamagata strains have been detected or genetically sequenced in flu case tracking, according to the researchers.
Only 31 suspected B/Yamagata cases were reported to public health officials during the most recent flu season, but no virus was successfully isolated or sequenced to determine whether B/Yamagata was to blame. According to studies, B/Yamagata has always been less contagious than the other major flu subtypes. Because the B/Yamagata strain doesn't develop as quickly as the others, vaccine producers haven't had to update the B/Yamagata component of the annual flu shot since 2015. The researchers stated in their analysis that these characteristics, "coupled with suppressive conditions of the COVID-19 pandemic, may have facilitated substantial suppression of worldwide B/Yamagata circulation and the potential extinction of this lineage." The study was led by Marios Koutsakos, a postdoctoral research researcher at the University of Melbourne. According to American infectious disease experts, if an entire strain of influenza has gone extinct, it will offer up new possibilities for combating the annual flu in the future.
They do warn, however, that determining whether B/Yamagata has died will require more than one flu season. "I'd be a bit hesitant to declare it a done deal," said Richard Kennedy, a prominent vaccine researcher at the Mayo Clinic in Rochester, Minn. "Flu is a temperamental little beast." He observed that B/Yamagata has a tendency to peak in certain years and then vanish in others. "Just because we haven't seen the facts in a while doesn't make it a credible argument," Kennedy added. "Data suggests that since March 2020, we haven't seen a single example, which is fantastic, but I'd prefer to see a longer period where we don't see any of it because these lineages were previously concealed from us." Now that COVID restrictions have been lifted and students have returned to school, public health officials are concerned that this flu season will be particularly difficult. He believes B/Yamagata will reappear.
"In this race, these viruses are quite good at making up for lost time and distance," Kennedy said. "We might gain ahead, but if we don't keep going, we won't be able to keep up." If B/Yamagata is gone, that implies we can juggle the strains in the annual flu vaccination to get more bang for our money, according to Dr William Schaffner, medical director of the National Foundation for Infectious Diseases in Bethesda, Maryland. Influenza A/H3N2 (Hong Kong), influenza A/H1N1 (Swine), influenza B/Victoria, and influenza B/Yamagata are the four strains included in the current flu vaccine.
Influenza A strains are more contagious and can cause epidemics, but influenza B spreads more slowly among school-aged children and teenagers. Every year, experts in the United States play a guessing game to see which genetic variant of each of the four strains is the most contagious, according to Kennedy. The flu vaccine delivers more protection when they predict correctly. According to Schaffner, replacing the B/Yamagata strain of the vaccine with a more infectious and deadly variant could boost the vaccine's effectiveness.
"Could you double up on H3N2, the next most dangerous strain? Is it possible to get two H3N2s in there?" Schaffner said. Kennedy concurred. "Being able to choose another strain that isn't B, that is an A strain," he said, "would help with that guessing game." The vaccine, on the other hand, might be reduced to only three strains, making the shot cheaper and easier to manufacture, according to Kennedy. "You have the option of producing more dosages or lowering the price slightly. As a result, the vaccination is more widely available "he stated
Kennedy and Schaffner agreed that if people obtain the flu shot this year and use COVID safeguards like masking and social distancing, B/Yamagata might be eradicated for good. "We did learn from the previous season that if you were serious about wearing masks and social distancing, staying at home, cancelling schools, and limiting travel, you could truly stop the annual influenza outbreak," Schaffner said. "I believe some of that will resurface, and I believe we'll see more of it in traditional public health recommendations."
As the flu spreads, people who are more likely to acquire a serious infection will be reminded to put on masks again, he said. "We're aware that they're no longer eccentric. They're employed all across the world, not just in Japan "Schaffner remarked. "Get your masks out; we know how to use them."
Article Credits: Dennis Thompson