How long does immunity last after you get the COVID vaccine? Do I need a third dose?

DETROIT – Since the coronavirus pandemic began, Dr. Frank McGeorge has been keeping viewers up-to-date and informed on all fronts. He’s been answering your questions about the vaccine, the vaccination process and more.

READ: More answers to questions about coronavirus


If I make a copy of the COVID-19 vaccination record card to keep as a backup in case I lose the original will it be accepted as proof of vaccination? Will I need to get a new proof of vaccination card?

A copy is a good idea, but keep in mind that the purpose of the vaccination card is to remind people which vaccine they received and when. It isn’t considered an official document for anything more than casual proof of vaccination.

As a heavy man should I get a third dose to ensure I have an adequate amount of vaccine in my blood?

No. There is no adjustment of the dose or additional doses recommended if someone is above their ideal body weight.

I had COVID from December through January. Very mild case. A co-worker has contracted COVID recently. Can I get it again? Or could I carry it to spread to others?

For people who have been infected, studies estimate that you should remain immune for at least three months.

My daughter said there is a study that reports that the COVID-19 vaccine shots only provide a 6-month immunity. Is that information true?

No. We don’t know how long protective immunity from the vaccines will last. That’s mainly because the vaccines only began their larger-scale trials in the latter part of last year. Data on long-term efficacy is still being collected.

Why is the second vaccine more prone to cause a reaction than the first shot? Is it more potent or made differently?

The second dose of the vaccine is the same as the first. The reason more people react to the second shot is that their immune system was primed by the first dose. That’s how your immune system works. Generally, the response to the second exposure is expected to be better.

I have had COVID-19 and recovered. How long do I have to wait to get the vaccine? I was told 90 days but just recently read online that they are saying 6 months. How long do I wait?

The reason for the wait is that while the vaccine was in short supply, people who had recent infection are already protected for at least 90 days and could wait to get vaccinated. Once the vaccine is more wildly available you do not need to put it off.

Is Emergency Use Authorization the same as FDA approval? If not, when will the vaccines be FDA approved?

Emergency Use Authorization is not the same as a full approval. The EUA is only valid while a public health emergency is in effect. After that, vaccines will require a full approval, which requires some additional data. The biggest piece will be a longer-term follow-up.

My daughter got a Ford Field appointment for the vaccine. She’ll be in Florida at the time of the second shot and will be home four days later. I know you said four days early is OK, what about four days late?

Four days early or four days late are both acceptable. The CDC said the second shot can be given as long as six weeks from the first, although that’s not ideal.


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