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With more than 230 million COVID-19 vaccines administered in the United States, many people are wondering when we can collectively ditch our masks and the social distancing to get back to normal. The answer, according to epidemiologists, is that it will take several more months before the nation can reach heard immunity.

Herd immunity is when the majority of a population becomes immune to a disease or virus, making transmission of that infection from person to person unlikely. There are two ways this can happen: natural resistance and vaccination.

When a person is exposed to a disease or virus, in this case COVID-19, the body will build antibodies as an immune response to fight off the infection. Even after recovery, those antibodies stick with you to help protect and defend against future infection.

Your body can also build immunity through vaccination. Vaccines can trigger the immune system into thinking you’ve been infected, even though you do not get sick. The body makes protective antibodies to fight future infection. Infections like measles, mumps and polio, which were once common in the U.S., are now rare thanks to vaccines that helped establish herd immunity.

image of Dr. Anna Giuliano

Dr. Anna Giuliano, Center for Immunization and Infection Research in Cancer

Dr. Anna Giuliano, an epidemiologist and founding director of the Center for Immunization and Infection Research in Cancer at Moffitt Cancer Center, says the U.S. will need at least 60% of the population to be vaccinated before we can reach herd immunity against COVID-19. But while more than 230 million doses of the vaccine have been administered, it is important to point out that only 94.8 million people have completed vaccination — or 28.9% of the population. In Florida, the fully vaccinated rate is 27.2%.

“Everyone, regardless of past infection with COVID-19, should be vaccinated as it very likely will lead to a more robust and longer lasting immunity to the virus,” Giuliano said. “Vaccination is the fastest way the nation can get back to pre-pandemic activities, like large-scale in-person events.”

Giuliano added that vaccination is also important because new mutations of the virus continue to emerge and spread.

“We are seeing another spike in coronavirus cases across the country, especially here in Florida. The increase is being driven by new variants of the virus that are highly transmissible and will continue to spread unless more people become immune,” she said.

If you have had COVID-19 and did not develop antibodies, which can be determined by a blood test, Giuliano says you remain susceptible to re-infection, especially to the highly transmissible variants that are circulating. 

“The easiest and safest way to achieve immunity for yourself and your community is by receiving the COVID-19 vaccine. But remember most vaccines have a 95% efficacy, meaning 5% of those vaccinated became infected in clinical trials. Nothing is 100% but vaccination comes close,” she said.