Intriguing new evidence has emerged that public health officials have underestimated the protection from COVID-19 that stems from recovery from infection.

Two major new studies suggest recovery from infection provides longer-lasting protection than the vaccines — especially if bolstered by even a half-dose booster shot.

Scientists have lacked strong, long-term data on the protection offered by so-called “natural immunity,” especially in the face of the fast-evolving strains of the virus.

Most measurements of immune response have relied on levels of fast-acting antibodies. Those measurements led many disease experts to think that the vaccines provided stronger protection than recovery from infection.

However, the new studies have focused attention on the role of the immune systems memory B and T cells, which keep a record of infections for a much longer time — orchestrating a rapid and effective response when the body encounters the virus a second time.

COVID-19 continues to spread in Navajo and Apache counties.

Navajo County has reported a 3% increase in cases as a daily average in the past two weeks and Apache County a 30% increase, compared to a statewide decline of 26%. Navajo County in the past two weeks has suffered in infection rate of 44 per 100,000 and Apache County a rate of 37, compared to a statewide average of 26. About 61% of eligible adults and teens are fully vaccinated in Navajo County and 72% in Apache County, according to CDC figures. However, that includes the highly vaccinated populations on the reservation. In the non-reservation portions of the county, only 38% are vaccinated in Navajo County and 28% in Apache County. So the non-reservation portions of Apache and Navajo counties have among the lowest vaccination rates in the country.

Navajo County reported 234 new cases off reservation for the week of Oct. 3-9, with an average age of 42, according to the County Health Department. That included 69 cases in Show Low and 31 in Pinetop Lakeside.

The tally for the week included 210 people who hadn’t been vaccinated — and 24 who had. Of that total, eight ended up in the hospital and three died — none of them vaccinated, according to the figures posted on the Navajo County Health Department website.

The new studies suggest natural immunity produces more of those memory cells than the vaccines.

However, the research suggests that both natural immunity and the vaccines get a second wind from a booster shot six months or a year later. At some point, these memory cells could provide protection against all strains of COVID-19 — or even against other SARS viruses. This might not include the common cold, which has proven adept at repeatedly infection the same person. The common cold is also caused by a SARS virus.

The most compelling evidence on the under appreciated protection offered by a prior infection comes from a massive study in Israel, the most highly vaccinated nation on the planet.

The Israeli study tracked tens of thousands of people this summer, when the delta variant dominated in the country. The researchers found that people who had recovered had greater protection against both reinfection and hospitalization than those who had two doses of the Pfizer or Moderna vaccines. However, a booster shot months after recovery from an infection provided the best protection of all.

The researchers stressed that people should still get a vaccine — and not wait to get infected. The disease itself carries far greater risks of both death and long-term disability than the vaccines. However, the study offers hope that the 44 Americans already infected — including 1.1 million in Arizona – will slow future spread of the virus more than previously assumed.

The study in Israel compared infections in the fully vaccinated to those who had recovered from a previous infection. The vaccinated had a six to 13-fold increased risk of infection compared to the people who’d recovered from infection. The risk of developing symptoms was 27 times greater and the risk of hospitalization was eight times greater.

However, those differences involved very small samples, since so few got infected. Only 238 of the 16,000 vaccinated people in the population got infected — about 1.5%. Only 19 of 16,000 people who had recovered from infection got infected a second time.

None of the people who had been vaccinated or recovered from an infection who then got infected died, according to a summary of the research published in the journal Nature.

The real-world study confirmed the picture that has emerged in laboratory and clinical studies, with findings published recently in both Nature and Immunity, peer-reviewed scientific journals.

Those studies have suggested “hybrid immunity” — produced by a combination of recovery from natural infection and a shot of one of the mRNA vaccines may provide the best protection from the widest variety of different strains, according to a summary of the research published in the journal Nature.

Both vaccination and natural infection prompt the body to make memory B cells, which carry a record of the proteins the virus uses to break into cells. Natural infection triggers antibodies that continue to grow in potency against different strains for at least a year. Those antibodies produced by vaccination stop changing and evolving after a couple of weeks or months. The booster may produce a fresh burst of change — in both natural infections and vaccinations.

The message of those studies seems clear.

First, get vaccinated — even if you’ve recovered from an infection.

Second, both vaccines and recovery from infection provide lasting immunity – and will play a key role in reaching the safety of “herd immunity.”

Peter Aleshire covers county government and other topics for the Independent. He is the former editor of the Payson Roundup. Reach him at paleshire@payson.com

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