Two shots of COVID-19 vaccine could be required | Daily News


Two shots of COVID-19 vaccine could be required

A vaccine against the Coronavirus may not be as simple as one jab and you’re immune.

There’s a high likelihood an eventual vaccine will require a two-dose series, a month or so apart, with the possibility of a booster several years later, adding to the complexity and cost of administration and distribution.

Much remains unknown about SARS-CoV-2, the virus that causes COVID-19. Even as physicians scramble to understand the natural history of the disease, scientists around the world are working to find vaccines to protect humanity against the virus. Only now are some of the broad outlines of what immunizations might look like becoming clear.

The two doses are likely to be required because SARS-CoV-2 is a newly emerged virus that no one has developed antibodies against. Also, with many potential vaccines being created using new systems it’s believed two doses will be required for full immunity.

The first shot would prime the immune system, helping it recognize the virus. The second shot would strengthen the immune response.

Of the more than 100 vaccine candidates in various stages of testing, almost all are expected to be a two-dose regime, said Barry Bloom, an immunologist and professor of public health at the Harvard T.H. Chan School of Public Health in Boston.

“As far as I am aware, with one set of exceptions, all the front-line vaccine developers are contemplating two shots,” he said. “The one exception is Merck, which last week pushed forward on two vaccines, each of which they hoped would be one-shot vaccines.”

The exact dosing will become clear as potential vaccines reach human clinical trials, said Dr. Kelly Moore, associate director of immunization education for the Immunization Action Coalition.

“The answer is to be found in the human studies that will show how we respond to the vaccine,” she said. “Phase 1 studies look at both dose size and, if animal studies suggest two doses might be needed, then they also look at one dose versus two doses.”


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