Why booster vaccines are given

This could suggest mixing and matching provided more protection — but antibodies aren't a perfect measure of overall immune protection. Regardless of what a person received originally, getting one of the three booster shots "led to good antibody responses," he said.

But it's unclear what the true effect of mixing and matching will be because real-world data is scarce. Even vaccines that use the same technology aren't identical, which could affect how a mix and match booster dose works, he said. For example, Moderna and Pfizer's vaccines both use a genetic code to teach the body to make part of the virus to trigger an immune response, but they vary in multiple ways including dose, dosing interval, and the genetic sequence they use.

Atmar agrees you'd test all combinations "in a perfect world," but that it wasn't "feasible" in the US to, for example, study "boosters in persons who had gotten AstraZeneca, or who had gotten the Chinese vaccine, or the Sputnik vaccine.

At the least, mixing and matching gives us options. In places where the same brand of booster isn't available, people can just take what's on offer. But no matter how effective they are, the extra protection won't be enough to end the pandemic, vaccine experts say. Eric Rubin, who sits on the independent vaccine advisory committee to the FDA, said last week. For you. World globe An icon of the world globe, indicating different international options.

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Barthelemy Saint Helena St. Kitts and Nevis St. Lucia Saint Martin St. Pierre-et-Miquelon St. Learn more about your flu vaccine options. For most individuals For seniors over 65 years.

Albert Travel Clinic. British Columbia. Schedule Your Appointment. The main goal is to give an extra layer of protection to older and medically fragile people. Experts agree that getting a booster too soon can reduce the benefit.

Timing matters because the immune system gradually builds layers of defenses over months, and letting that response mature improves the chances another, later dose will provide even stronger protection. That gives flexibility in situations such as nursing homes where health workers on booster visits may bring only one type. It also gives people at risk of a rare side effect linked to one kind of vaccine the option of switching to a different shot. Preliminary results of a government study found an extra dose of any vaccine triggered a boost of virus-fighting antibodies regardless of what shots people got to begin with.

But researchers cautioned the study was too small to say one combination was better than another, and only measured antibodies when the immune system forms additional layers of protection. Nobody knows.