COVID-19 Update: 73% of Americans Likely Immune to Omicron

Covid Update

Is it possible the U.S. has turned the corner on the pandemic? At least one computer model suggests that if we don’t get another highly transmissible variant, we might be, with almost three-quarters of Americans likely immune to Omicron. Unfortunately, there are still at least 7 million people with a suppressed immune system that may always be vulnerable. For that and more COVID-19 news, continue reading.

About 73% of Americans Likely Immune to Omicron

Approximately half of the eligible people in the U.S. have received booster shots against COVID-19. In addition, about 80 million people have had confirmed infections, with even more unconfirmed. At least one model from the University of Washington’s Institute for Health Metrics and Evaluation estimates that at this time, 73% of Americans are immune to Omicron, and it could rise to 80% by mid-March. If another even more transmissible variant or one that is so different from the previous ones that our immune systems don’t recognize it, this would seem to be good news.

“We have changed,” said Ali Mokdad, a professor of health metrics sciences at the University of Washington in Seattle. “We have been exposed to this virus and we know how to deal with it. I am optimistic even if we have a surge in summer, cases will go up, but hospitalizations and deaths will not.”

Despite that, the U.S. is seeing more than 130,000 new infections and more than 2,000 deaths per day. There are still tens of millions of people unvaccinated or unexposed who are vulnerable. In the U.S., approximately 3% of adults are on immunosuppressive drugs to treat cancer, autoimmune diseases, or prevent the body from rejecting transplants or stem cells. That comes to 7 million people and doesn’t include those with HIV and at least 450 other genetic disorders.

Updates on Omicron-Specific Boosters

Moderna indicates that an Omicron-specific booster shot may be ready by August. However, it is still collecting clinical data to decide if that would provide more protection than a fourth dose of the existing shot. Preclinical data in monkeys suggests an Omicron-specific shot might not offer stronger protection than the existing shots.

Stephane Bancel, Moderna’s chief executive officer, said, “We believe a booster will be needed. I don’t know yet if it is going to be the existing vaccine, Omicron-only, or bivalent: Omicron and existing vaccine, two mRNA in one dose.”

Moderna also hopes to have a pan-vaccine ready by August 2023 that would protect against COVID-19, influenza and other respiratory illnesses. The company also plans to expand its commercial activities in Europe in hopes of improving sales there.

In a related story, Pfizer and BioNTech say their Omicron-specific vaccine has been delayed by several weeks because data-gathering has been slower than expected. Once it’s ready, like Moderna, the companies will decide if it’s still needed.

BioNTech’s chief executive officer Ugur Sahin said, “If the wave ends, that does not mean it can’t begin again,” adding, “I really don’t see the situation as dramatic anymore,” referring to how quickly they can develop and modify mRNA vaccines.

Vaccine-Related Myocarditis May Be Milder than From Other Causes

Although rare, cases of heart inflammation called myocarditis are associated with the Pfizer-BioNTech and Moderna COVID-19 vaccines. A study out of the University of Toronto suggests that these cases are generally less severe than seen with other causes. They retrospectively evaluated the electronic health records of 92 adults diagnosed with myocarditis from December 2019 to November 2021. 

Of them, 22% reported myocarditis within 14 days after being vaccinated, 11% after COVID-19 disease, and 66% from other causes (non-COVID-19 infections (31%); autoimmune disorder (13%); drugs (5%); hypereosinophilic blood disorder (5%); other/unknown (41%). They point out that the risk of myocarditis is much higher after COVID-19 infection than it is from vaccination.

Alvea Expects Clinical Tests of Omicron Subvariant BA.2 Vaccine to Start in March

Alvea has tested its vaccine against the Omicron subvariant BA.2 in animals and expects to start clinical trials in March. It is a DNA vaccine, which is reported to be stable at room temperature for more than three months. The company believes if it gets approval, it will be targeting low and middle-income countries. Like mRNA vaccines, the vaccine uses DNA to provide the codes for viral antigens; unlike mRNA, DNA vaccines are stable at room temperature.

“Because our vaccine is extremely simple — just plasmid DNA in a common buffer, the manufacturing process is much more straightforward than for mRNA or viral vector vaccines,” a company spokesperson said. “In fact, plasmid manufacturing is commonly the first of many steps used to produce mRNA or other vaccines, whereas in our case, it’s the only step. And we estimate that there is sufficient fill/finish capacity around the world to support that part of the process.”

J&J and Pfizer-BioNTech Vaccines Equivalent in Kidney Dialysis Patients

DaVita Clinical Research published a study in the Journal of the American Society of Nephrology that found that kidney dialysis patients who received the Johnson & Johnson vaccine had similar rates of breakthrough infection, hospitalization and mortality as patients who received the Pfizer-BioNTech vaccine. This patient population is typically reviewed as immunosuppressed. Both vaccines were about equal at reducing the risk of hospitalization and mortality from a breakthrough infection.

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