Report: 1% of Alaska COVID cases were reinfections

ANCHORAGE, Alaska (KTUU) - Nearly 900 Alaskans have had COVID-19 more than once, state data released late last week shows, and the natural immunity that provides is showing to be somewhat protective against reinfection. However, data suggests it’s still not as effective at preventing reinfection as a COVID-19 vaccine.

“Prior infection with SARS-CoV-2 confers substantial but not complete protection against subsequent infection,” the report reads. SARS-CoV-2 is the scientific name for the virus that causes COVID-19.

The state’s monthly report on COVID-19 cases for August took a retrospective look at confirmed cases and tallied people who have had more than one confirmed case of COVID-19. Six people were tallied as having had COVID-19 three times.

The 884 reinfections were counted since the beginning of the pandemic. That’s just 1% out of 87,836 residents with at least one case that were tallied through Aug. 31. In July and August of 2021, when the more transmissible delta variant took hold in Alaska, a person who had not had COVID-19 was more than four times more likely to get COVID-19 than someone who had the disease before, the report said.

Dr. Joe McLaughlin, the state epidemiologist, said late last month that natural immunity after a COVID-19 infection varies person to person, but a person who was more ill may mount a stronger immune response when facing the virus a second time.

“They were exposed to so much virus over such a long period of time that their body’s immune system is completely primed and prepped and ready to see another presentation of the virus down the road,” he said.

However, state data show that in July and August, people with a prior history of having COVID-19 who who did not get a vaccine were still 24% more likely to be reinfected than those who got vaccinated after their first infection.

The state says there were too few hospitalizations among reinfection cases to detail natural immunity’s impact on hospitalizations, “though the available evidence is suggestive that vaccination confers additional protection in persons who have been previously infected,” the report states. Five unvaccinated people who had previously had COVID-19 were hospitalized for it in July and August. One person who had been previously infected and vaccinated was hospitalized for COVID-19. Two people who died of COVID-19 in those months were unvaccinated and had had a prior infection.

The report states that it may not be a complete look at the issue in Alaska, as it’s dependent on the number of positive tests reported to the state, and cases may go undiscovered.

“(This report) does not account for differential testing rates that might occur between vaccinated and unvaccinated people,” it states.

Undetected COVID-19 cases in untested, unvaccinated people may make the data appear to show that vaccines are less effective, the report says, if vaccinated Alaskans are more likely to get tested for COVID-19.

Even with some immunity protection, the state report and state doctors say the best way to reduce the spread of COVID-19 is through vaccination and “non-pharmaceutical mitigation strategies,” which include masking, social distancing and avoiding crowded indoor areas.

The Centers for Disease Control and Prevention recommends both vaccinated and unvaccinated people wear masks in indoor public areas in places with high rates of COVID-19 transmission, which includes the entire state of Alaska.

“We know our vaccination rates are not as high as the national average, so that’s going to help drive transmission, and then also the degree to which people are social distancing, avoiding crowds, wearing masks, avoiding indoor spaces where lots of people are congregating,” McLaughlin said. “If people are doing that regularly throughout Alaska, you’re going to see less transmission. If people are not following those non-pharmaceutical mitigation strategies, you’re going to see more transmission.”

Clarification: This story has been edited to clarify that a person who had not had COVID-19 was more than four times more likely to get COVID-19 than someone who had the disease before, according to state data from July and August. The original sentence had a typo that did not make the distinction clear. This article has also been edited to clarify that the number of residents with at least one COVID-19 case were tallied through Aug. 31.