Dr. Scott Gottlieb. the former chief of the Food and Drug Administration, told CNBC recently that there’s another reason besides the COVID-19 vaccine as to why coronavirus cases are dropping, and it has to do with people already infected.

Why are COVID-19 case numbers dropping?

For the most part, the COVID-19 vaccine has impacted the infection levels of the novel coronavirus. More vaccinations have led to a slowdown in cases, Gottlieb said.

  • But there are other factors, too, including “warming weather and the fact that a portion of the unvaccinated population has already been infected with COVID,” according to CNBC.
  • “We don’t have data on this, but my guess would be that the infection level among the unvaccinated population is probably higher because a lot of people probably aren’t getting the vaccine because they knew they were previously infected,” Gottlieb told CNBC.
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For example, the Deseret News reports that about 36.6% of the Utah population has been fully vaccinated against the novel coronavirus, But there’s another 13% who haven’t been vaccinated but have some level of immunity because they were previously infected.

How long does immunity last?

But remember — it’s unclear how long natural immunity lasts. So far, research has signaled the natural immunity built up from antibodies can last around six months.

Still, researchers have pushed people to get vaccinated over relying on natural immunity, saying the COVID-19 vaccine is the best way to stay safe.

  • “You can certainly not rely on a past infection as protecting you from being ill again, and possibly quite ill if you are in the elderly segment,” Steen Ethelberg, an epidemiologist at Statens Serum Institut in Denmark, told The New York Times.