The Yearly Flu Shot Could Soon be a Thing of the Past

A century after one of the world’s deadliest pandemics, scientists are making progress on a universal flu vaccine

In 1918, in the final months of World War I, a flu pandemic spread across the world. It may have started among Chinese laborers who were transported in trains across Canada, and was first identified in the U.S. in soldiers. In the absence of vaccines, or antibiotics to treat secondary bacterial infections, the pandemic would eventually infect 500 million people and kill 50 million — 3% of the global population — making it the deadliest pandemic in history after the Black Death.

Twenty years later, legendary immunologist Jonas Salk and his New York University mentor Thomas Francis developed the first flu vaccine. Their discovery, which was first tested on U.S. soldiers in World War II, laid the groundwork for Salk’s revolutionary later work on a polio vaccine.

But in the mid 1940s, as the vaccine became publicly available, researchers began to notice a troubling trend: For reasons that are still not entirely understood, the genes of the flu virus tend to “drift” year to year, creating slight mutations that can render last year’s vaccine ineffective. That’s why the flu season is a never-ending game of immunological whack-a-mole, in which scientists at the World Health Organization (WHO) and other agencies — like the U.S. Centers for Disease Control (CDC) — make an informed guess about what change might occur and preemptively design a new vaccine to protect against the new viral strains.

For the most part, they’ve been remarkably successful: The seasonal death rate from flu in the U.S. in the 1940s was around 10 per 100,000 people; by 2017, it was around two. But the disease still sickens up to five million people globally each year. In most seasons, the vaccine works less than half of the time.

Now, a century after the pandemic, scientists are closing in on the ultimate prize in immunology: a so-called universal flu vaccine that would counter most, if not all, flu strains and would…