A Warmer Climate Could Make Every Season Flu Season

The flu has a paradoxical relationship with the weather. In the United States, the flu thrives in the winter, when the air is cold and crisp, and then ebbs in the spring, when the disease is stymied by hotter temperatures. Still, in equatorial countries, where it is usually warm, humid and rainy, people get sick with the flu all year round. Scientists are studying why this happens, but they have no answers as of yet.
It’s a real puzzle, since flu viruses spread more easily in cold, dry air than in heat, but they are a perennial problem in the tropics.
This contradiction could have major implications for the future of the flu in the United States. While climate change promises shorter, warmer winters, which could yield milder flu seasons, scientists say that the way the flu operates in the tropics suggests that in the coming decades, warmer, wetter weather could make the flu a year-round problem for Americans.
“It would not be surprising to see the year-round influenza zone expand as the world warms,” says Robert. T. Schooley, an infectious diseases specialist and editor of the journal Clinical Infectious Diseases.
Schaffner agrees. “A warm climate promotes sustained transmission as opposed to seasonal outbreaks, so we might get flu year-round,” he says.
A longer flu season could upend annual vaccination programs. The flu vaccine grows less effective over time, especially in the elderly. That’s why public health officials urge Americans to get vaccinated in the fall, so they are best protected through the winter. If the flu becomes a perennial problem, people might need to get vaccinated more than once a year, a prospect that makes health experts shudder.
It’s tough enough to convince people to get annual flu vaccinations — fewer than half of American adults were vaccinated last year — let alone encourage multiple injections throughout any given year. Moreover, scientists must begin producing vaccines long before flu arrives, determining which strains to vaccinate against based on which stains are circulating in other parts of the world during their winters. This process would become more complicated if scientists had to keep pace with waning immunity or a virus that is constantly changing.

By – Abhishek Singh
Content - https://www.popsci.com/story/health/flu-climate-change-bad/