State health officer weighs in on COVID-19 vaccines vs. natural immunity

Published: Nov. 3, 2021 at 7:50 PM CDT|Updated: Nov. 3, 2021 at 10:23 PM CDT
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MONTGOMERY, Ala. (WSFA) - Health experts are learning more about the level of protection the COVID-19 vaccine provides.

A new study from the Centers for Disease Control and Prevention (CDC) offers more evidence that getting vaccinated provides stronger immunity against COVID-19 than past infection.

As research has shown, previous infection of the virus provides some degree of immunity and protection against getting COVID again, but according to the study, protection from the vaccination is stronger.

The study looked at data from nearly 190 hospitals in nine states. Researchers counted about 7,000 adult patients hospitalized with COVID-like illnesses and found that those who were unvaccinated - but were infected with COVID months earlier - were five times more likely to be reinfected with the virus compared to those who were fully vaccinated and had not had COVID before.

About 6,000 of them had been fully vaccinated with the Moderna or Pfizer vaccines three to six months before they wound up in a hospitals. The other 1,000 were unvaccinated but had been infected with COVID-19 three to six months earlier.

About 5% of the vaccinated patients tested positive for the coronavirus vs. about 9% of the unvaccinated group. The researchers factored in other data points, including age and how much virus was circulating in different areas, to calculate that the unvaccinated group was at even higher risk.

“The immunity from the vaccine is more protective and more predictable than the immunity that people get from natural infection,” said State Health Officer Dr. Scott Harris.

Harris said the heart of the problem remains the inability to know just how long someone’s immunity from the virus will last after being infected. That is something he said cannot be tested and is still being studied.

But, Harris said one thing we do know is that “the most robust immunity responses we see are in people who have been infected before who then go and get vaccinated. And so if people have been previously infected they absolutely need to be vaccinated anyway.”

Health experts have seen that antibody levels provided by the COVID vaccine begin to decline after about 6 months, which is why booster shots are encouraged.

How often we will need to get booster shots in order to obtain the highest level of protection from COVID-19, is also still being studied.

“I think people are going to always need booster shots at some point, whether that turns out to be once a year or maybe after people get their first booster dose it’s a couple of years before they need another one, we just don’t really know right now,” Harris said.

The CDC study only included adults fully vaccinated with Moderna or Pfizer’s vaccine. The study’s authors noted that protection from Moderna’s vaccine “appeared to be higher” than for Pfizer’s vaccine.

The boost in protection from vaccination also “trended higher” in adults 65 and older compared with people ages 18 to 64.

Because the study only included people vaccinated or previously infected within the previous six months, the researchers cautioned that the protective effects may wane over time.

The analysis did not include adults who received Johnson & Johnson’s COVID-19 vaccine, who are currently recommended to receive a booster shot at least two months after they were first vaccinated.

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