Vaccines are one of the greatest scientific discoveries in human history. They eradicated a disease, smallpox, that killed 300 million people in the 20th Century. They save countless lives every year, protecting against diseases caused by viruses like polio, measles and yellow fever. But some viruses are particularly difficult to target with vaccines.

We need a flu shot every year because the virus mutates so much previous vaccines may no longer be effective. Scientists are closer than ever before to developing what are known as universal vaccines. These vaccines would protect against many variants of a given virus, and potentially against entire virus families. Viruses are constantly mutating, but only some of those mutations are important.

For example, a change in the shape or chemical properties of the spike protein a virus uses to infect a cell could make the virus more transmissible. It could also mean antibodies developed from previous infection or vaccination wouldn’t be able protect against the current virus. But, there are some sites on viruses that don’t mutate as much, or at all. These sites are often vital to the virus’ survival. Scientists are using powerful technologies to identify antibodies that target these sites.

They’re called broadly neutralizing antibodies and are capable of protecting against multiple viral variants. Now, researchers are working to design shots that get our bodies to produce broadly neutralizing antibodies. Meaning someday soon, vaccines for HIV, flu and coronavirus might be enough to effectively ward off these viruses for the better part of a lifetime.