COVID-19 Vaccine Takes 6-8 Weeks After 1st Dose to Reach Full Efficacy, Expert Says

Doctors say while data shows the initial dose of the two-dose vaccine may offer some protection, it's still possible to catch the virus.

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Despite getting the first dose of a COVID-19 vaccine, there have been reports of some still testing positive for the virus.

It happened to U.S. Rep. Kay Granger (R-Fort Worth).

She got her first shot of the COVID-19 vaccine last month and tested positive for the virus in Washington before Congress reconvened.

"We know that one dose gives partial protection and a second dose gives near-complete protection," said Baylor Scott & White internal medicine practitioner Dr. David Winter.

Winter said partial protection means you still have a 50% chance of getting COVID-19, after just one of the Pfizer shots.

Moderna has not published its vaccine's level effectiveness after one dose.

Both vaccines require two doses to reach their maximum potential of around 95% effectiveness.

While one dose leaves still leaves the recipient open to to getting COVID 19, it may lessen the symptoms if the virus is caught.

"We know from influenza shots, we give a lot of flu shots every year and I get half a dozen who get the flu but a very mild case of it. So, by that analogy, if you get one shot or you get two and you get the virus, you still should have a very mild case of it," Winter said.

He said what isn't likely is that the vaccine will result in a positive COVID-19 test because he says, the vaccine has no live virus in it.

The only test that would pick up any change in your body would be an antibody test that would detect the new COVID-19 antibodies produced by your immune system after the vaccine, Winter said.

"Neither the rapid test, that looks for antigen, a portion of the virus itself, or the PCR swab, those should be both be negative after you get COVID-19 vaccine," he said.

Winter said both the Pfizer and Moderna vaccines will reach that 95% level of effectiveness around six to eight weeks from your initial dose and only, of course, if you get the second shot.

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