Do you need a vaccine if you had COVID-19? What health experts want people to know.

Doctors warn antibody tests shouldn't be used to determine when to return to work
Posted at 5:42 PM, Oct 14, 2021
and last updated 2021-10-15 09:52:38-04

Recently there's been a lot of conversation surrounding natural immunity for COVID-19, with some insisting they might not need a vaccine because they already had the virus.

The question of natural immunity versus the COVID-19 vaccine has also been brought up by state lawmakers and those who are hesitant about vaccine mandates.

“We’re almost 20 to 21 months into knowing about this novel coronavirus and how our immune system responds. We're still looking at the data and were still learning about how well we may be protected not only from natural infections should that happen, but with the vaccine as well,” Regence Executive Medical Director Dr. Amy Khan said.

In Idaho over 272,000 people have contracted COVID-19 since the start of the pandemic and Wednesday there were over 2,000 new and confirmed positive cases reported to the state.

Health experts say while yes, you will build up natural immunity, the severity of illness from prior infection can determine how much natural protection someone has.

“What most people are talking about in this context are antibodies and those antibodies that are produced and stay in the bloodstream. Those antibodies that are produced then can be secreted onto mucosal surfaces such as our nose or mouth and gi tract. There's another arm that is not easily measured which we call T –cells. So when you have a natural infection there are a whole host of proteins that the virus produces or induces and any of those proteins or various aspects of those proteins can stimulate a response by the immune system,” Physician and Infectious Disease Doctor Dr. Sky Blue said.

The severity of the COVID-19 infection typically determines how your immune system builds up antibodies. A mild infection would generally leave someone with a lower level of immunity where a severe one might offer higher levels that could last longer.

“It's certainly shown that someone who has recovered probably has better immunity than someone who has never seen this virus,” Blue said.

Alternatively, Blue said severe and critical illness like a hospitalized individual can actually have a counter effect harm the areas of the body that create immunity like lymph nodes and reduce the long-term effect.

Is this protection from natural immunity for someone recovered better or the same as a vaccine? The answer is complicated. For those who have recovered, it's unclear where someone might be on the spectrum of immunity, but Blue said there is evidence that having some immunity built up will impact future infections.

“With a natural infection, we have nearly an infinite number of other proteins that you can also direct immune response to which will not necessarily be protective,” Blue said. “Recovery, in general, does lead to some immunity and that immunity can be enhanced by a vaccine.”

While some might have the natural antibodies from a previous infection, they might not help for a new COVID-19 variant.

“Having some immunity built up can protect from severe illness, going forward, it may or may not carry over to new variants,” Blue said.

“We have a new variant in town, right? The Delta variant is much more transmissible and is different than that initial strain and so we don’t know exactly how people who have been naturally infected are going to respond. We do appreciate they have some likely recognition but we’ve seen reinfections do occur,” Khan said.

Without the boost of protection from a vaccine, antibodies can weaken over time, leaving COVID-19 recovered people at risk of another infection or spreading the virus.

“We're getting an ever-increasing amount of data that’s saying that vaccination after natural infection remains very safe,” Blue said.

Only 53% of Idaho's population ages 12 and older are fully vaccinated, and according to the Department of Health and Welfare, 87% of the deaths have been among those unvaccinated.

“The data is clear. People who have been vaccinated have a much lower rate of having significant cases and have a much lower rate of being hospitalized and dying,” Khan said.