Omicron has shattered what we know about COVID reinfections. Here's why you may be vulnerable.
Initially, enduring COVID had one redeeming quality: It gave you some short-term immunity from getting infected again.
But the new Omicron subvariants are shattering that trend. BA.5 has caused more people to catch COVID for the second or third time than previous strains.
BA.5 is known for having a structure that is maximized to evade immunity and for transmitting from person-to-person more easily than other subvariants in the Omicron family.
Here's what you need to know about reinfections.
Reinfections are increasing
Emerging research shows the percentage of reinfections is rising.
Helix, which sequences COVID-19 tests to surveil variants, found out of nearly 300,000 infections since March 2021, the share that was reinfections almost doubled to 6.4% during the BA.5 wave in July from 3.6% during the BA.2 wave in May.
The Helix data shows that most reinfections in July occurred in people who had COVID-19 in 2021.
Experts expect the rate of reinfections to continue to climb for two main reasons: BA.5 is highly contagious, and the majority of the country has already contracted COVID-19 at least once.
Early in the pandemic, strains like delta weren't replaced as fast by new variants and people who had COVID-19 had some protection against reinfection for several months. But now, new strains are sweeping through the country one after the other.
Just since April, BA.2, BA.2.12.1 and now BA.5, have had turns at being the dominant strain. So Floridians who got an earlier variation of Omicron in spring could be vulnerable to reinfection from a different strain circulating this summer or fall.
Experts differ on how soon you can get reinfected
As a nation, no one knows the true magnitude of reinfections because people are testing at home or they aren't testing at all.
However, researchers feel confident chances are higher of getting COVID again if you had the virus or your most recent vaccine dose prior to 2022. Shishi Luo, associate director of bioinformatics and infectious disease at Helix, said her data shows on average, people who are getting reinfected now were last infected about nine months ago.
So does that mean if you had COVID-19 in the last few months, you likely won't get it again this summer or fall?
That answer differs depending on who you ask.
A new study backs up the notion that a previous Omicron infection could offer some protection from BA.5., the newest strain. When analyzing COVID-19 cases recorded in Qatar between May 7 this year—when BA.4 and BA.5 first entered the country—and July 4, researchers found prior infection with Omicron was 79.7% effective at preventing BA.4 and BA.5 reinfection and 76.1% effective at preventing symptomatic reinfection.
"Basically you have a seven times greater chance of being reinfected if your previous infection was before Omicron," said Dr. Michael Daignault, an emergency physician at Providence Saint Joseph Medical Center in Burbank, Calif. "The immunity from a previous Omicron infection actually protects you from other Omicron sub-lineages to some extent, but nothing is 100%."
Daignault also referenced a new Danish pre-print paper released this week that shows high protection against BA.5 in people who are triple vaccinated and had a prior Omicron infection. Daignault said he had COVID-19 for the first time in June and doesn't worry about reinfection—at least for now. "I am a young healthy guy who is triple vaccinated and recently infected. I feel well protected."
Many experts, however, believe reinfection risk varies by individual. In some parts of the country, cases are being reported of reinfections in as early as one month.
Some of Florida's seniors may find themselves in that situation, said Dr. Mary Jo Trepka, an infectious disease epidemiologist with Florida International University.
"Your chances of reinfection can depend on whether you have been vaccinated and are up to date on your booster, what your previous infection was like and how far away it was, since immune defenses tend to wane over time," she said. "It also could depend on your age and underlying health conditions."
Trepka said even with immunity from a recent infection, the circumstances play a role in whether you catch COVID again. "If you have a fleeting encounter with someone outdoors, you would be exposed to a smaller viral load than if you are living with someone infected who has a higher viral load."
Symptoms may differ each time
Doctors see evidence that symptoms tend to be milder and shorter if you get COVID-19 a second or third time, but it's hard to firmly say that this will be the case for everyone. You may still run a fever and experience exhaustion, a sore throat, brain fog and other symptoms.
Dr. O'Neill J. Pyke, chief medical officer at Jackson North Medical Center, said he contracted the original strain of COVID-19 in 2020. He could barely breathe, lost 20 pounds and missed 45 days of work.
Pyke caught another case of COVID-19 last month. By now he had been vaccinated and had a booster shot seven months earlier. This time he had a horrible headache and fatigue.
"It was just a bad three days," he said. After six days, he was able to go back to work.
In looking at Jackson's COVID hospitalizations, Pyke says it is possible that people who are highly vulnerable to the virus and got really sick during an earlier infection may experience severe symptoms during reinfection. It also is possible, he said, that someone healthy, vaccinated and recently infected could have symptoms so mild they don't know they have COVID unless they are tested for work or other reasons.
Reinfections come with risk
Experts still don't have the full picture of what kind of health risks come from having COVID over and over, but a new study aims to offer some insight.
Ziyad Al-Aly, a clinical epidemiologist at Washington University and chief of research and development at the VA St. Louis Health Care System, used the health records of 5.7 million American veterans to gauge reinfection risk. He discovered that every time you contract COVID, your chance of getting really sick with something such as clotting or lung damage seems to go up. The risks remained whether or not people were fully vaccinated.
"It is also possible that the first infection may have weakened some organ systems and made people more vulnerable to health risks when they get a second or a third infection," Al-Aly told WebMD.
The results of his research were published online June 17 as a pre-print study, which means it has not yet been peer-reviewed.
How to prevent reinfection
COVID fatigue has set in, masks are off and crowds are gathering indoors again, just as BA.5 has come along and is highly contagious.
Getting vaccinated or boosted is a good way to keep your immunity levels high and ward off severe disease. You only need to wait a few weeks after an infection to get a shot, the CDC says.
Dr. Cory Harow, an emergency physician at West Boca Medical Center, says staying up to date with shots "really does make a difference, especially in people who are older."
"With more COVID in the community, more and more people are becoming ill enough to require admission to a hospital," he said.
Harow said if you have an upcoming event or travel and want to avoid reinfection, even if you have had Omicron, wear a mask in crowded places and make sure to get boosted. "If you want to lower your chances, it's something to consider."
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