Oklahoma State Department of Health data shows a person is twice as likely to get a reinfection of COVID-19 than a breakthrough case.
A reinfection is when someone got the virus, is not vaccinated, and then gets the virus again after recovering.
A breakthrough case is when someone has been fully vaccinated and then gets the virus despite having the vaccine.
Local doctors said there are a few reasons for this.
"It is very clear, just because you had it once, doesn't mean you won't get it again, and you won't fight it off easily the second time," said Dr. Mary Clarke, the Oklahoma State Medical Association president.
To date, OSDH officials reported reinfection cases sit just under 1,100 per 100,000 eligible cases, but breakthrough cases sit at almost 560 per 100,000 fully vaccinated Oklahomans.
"Someone who had an infection in January, February or March, they got infected with the alpha variant, so the protection they got may not be effective against the delta variant," said Dr. Dale Bratzler, OU Health's Chief COVID-19 Officer.
With reinfections, Bratzler said natural immunity wanes quickly, within 90 days of recovering. If you had a mild case of the virus, your natural immunity may not be strong.
"You may not have generated a good immune response and may not have very good protection," said Bratzler.
Health professionals, like Clarke, said breakthrough infections are not as common due to the immune response created by the vaccine.
"Vaccines have some form of adjuvant that boosts the immune system, so it's much higher over time," said Clarke.
That doesn't mean breakthrough infections don't happen for a couple of reasons.
One, doctors said the delta variant is more transmissible. Second, those who received the vaccine when they first came out, like the elderly, might have dwindling antibodies.
"So, the farther you are from that second dose of the vaccine, you have less antibody to fight off an infection," Bratzler said.
Bratzler said boosters could help reduce the breakthrough cases, as well as our case count overall.