Increased infectious strain and lack of vaccination led to outbreaks of H3N2 influenza

The Putantan Institute issued an alert about the outbreak of H3N2 influenza cases across Brazil and linked the growth to the most transmissible strains, decreased influenza vaccination across the country and reduced preventive measures in the epidemic, which is related to influenza, which has the same precautions as Covid-19, because respiratory illness; The scientific entity also confirmed that the absence of masks and the return to intensive activities in person at the end of the year were factors that contributed to the increase in infection with the H3N2 virus.

“The cause of the H3N2 (Darwin) influenza outbreak across the country is not isolated, but the result of several factors that allowed the virus to spread,” the institute says. According to Butantan’s director of production, Ricardo Oliveira, who is responsible for distributing a flu vaccine in 2021, lowering Covid-19 preventive measures combined with lower immunization may explain the current outbreak. The off-season outbreak may be related to the fact that the H3N2 strain appears to be more transmissible. In addition, the population prioritized vaccination against Covid, and as a result, influenza vaccination coverage did not arrive as expected and more people were left without protection, which reinforces the importance of vaccination,” he adds.

Other points are the resumption of face-to-face activities and the relaxation of measures to contain Covid-19, such as the use of masks, which are part of Brazil’s anti-influenza campaign. And the director stresses that “the flu has found a good opportunity to spread with reducing the distance and resuming activities as a whole.”

H3N2 and its spread to other countries

According to Renato Astrai, Director of the Multipurpose Laboratory of the Butantan Institute, the outbreak occurred in the middle of summer in Brazil, which is unusual, given the fact that H3N2 influenza was already widespread in other countries, and gained strength in the Brazilian context after that. Resuming travel and reopening activities, while easing preventive measures such as the use of masks. “We’ve been using a mask for two years and it protects against both influenza and SARS-CoV-2 because it prevents contact with respiratory viruses, but these measures have been relaxed and people are more exposed to contact with these viruses,” he explains.

Influenza vaccination is necessary

According to Putantan, the influenza vaccines being applied to the Brazilian population in the 2021 immunization campaign were produced by the institute and transferred to the National Immunization Program of the Ministry of Health. “The institute sent 80 million doses to the federal government, which made them available free of charge through the unified health system to the public most vulnerable to disease. To prevent an unreasonable outbreak of disease from spreading further, Butantan donated 1.4 million doses to the cities of São Paulo (one million) and Rio de Janeiro (400 thousand), based on requests from the municipal health secretariats. He stressed that the focus of this distribution was on people who did not take the immunizing agent during the campaign.”

“In Brazil, last year’s influenza vaccination campaign started in April and continued until September in an effort to reach all priority audiences. The elderly, pregnant women, postpartum women, children, indigenous people and health professionals most at risk of infection were the focus of the campaign, which ended without a vaccination target being reached. 90% of this population, according to the Ministry of Health. Health ”, concludes the press office.

With information from Putantan Institute