Two years after the coronavirus pandemic, Americans can be forgiven if they have lost sight of the latest options circulating in the country and around the world. We have heard about alpha, beta, gamma, delta and omicron variants, but a new version with Greek letters has not appeared on the scene for almost half a year.

Instead, the last few months have seen a seemingly endless stream of “subvariants” of omicron, the latest version of Greek letters.

How different are these sub-options from each other? Can an infection from one sub-variant protect someone from infection from another sub-variant? And how well do existing coronavirus vaccines, which were developed before omicron, work against sub-variants?

We asked these and other questions to medical and epidemiological experts. Here is a brief.

Question: What are the sub-options? How different are they from each other?

Omicron subvariants look like an alphabetic soup of letters and numbers. The original version of the omicron was named B.1.1.529. The original variant of omicron gave birth to such subvariants as BA.1; BA.1.1; BA.2; BA.2.12.1; BA.3; and the latest BA.4 and BA.5.

“They all differ from each other by having different mutations in spikes protein“Which is the part of the virus that enters host cells and causes infection,” said Dr. Monica Gandhi, a professor of medicine at the University of California, San Francisco.

Small to moderate mutations in these subvariants can make them slightly more transmissible from person to person. In general, the higher the number after ‘BA’ in the name of the sub-variant, the more portable this sub-variant. For example BA.2 is it is believed to be about 30% to 60% more marketable than previous sub-options.

These mutations allowed only the subvariants to spread widely to be ahead of time from a slightly more portable sub-option within a few weeks. The process is then repeated.

In the United States, for example, BA.1.1 was dominant at the end of January, ahead of the original, B.1.1.529. But by mid-March BA.1.1 had begun to lose ground BA.2, which became dominant in early April. By the end of April, another sub-variant – BA.2.12.1 – was gaining strength, representing almost 29% of infections, according to data from the Centers for Disease Control and Prevention. (The Delta wave of late 2021 was not a factor during this time.)

Question: How about the severity of the disease?

Fortunately, the diseases caused by omicron are usually less severe than those caused by previous variants – a model that seems to be valid for all subvariants studied so far. An analysis from Denmark showed that BA.2 no longer causes hospitalization than sub-option BA.1, Gandhi said.

Even the newest sub-options found, BA.4 and BA.5“There is no evidence to suggest that it is more alarming than the original Omicron, other than a potentially slight increase in transmission,” said Brooke Nichols, a mathematical model of infectious disease at Boston University.

Dennis Cunningham, System Medical Director for Infection Control and Prevention at Henry Ford Health in Detroit, told NBC News that the symptoms of omicron subvariants “are quite consistent. There are fewer cases of people who lose their sense of taste and smell. In many ways it is a bad cold, many respiratory symptoms, stuffy nose, cough, body aches and fatigue.

Q: If you become infected with one sub-variant, will you be protected against others?

So far, in all variants so far, the virus’s ability to evade existing immune defenses. “is only partiallike the seasonal flu, ”said Colin Russell, a professor of applied evolutionary biology at the University of Amsterdam Medical Center.

While some people who have had BA.1 have also received BA.2, initial research suggests that BA infection. 1 “provides strong protection against re-infection with BA.2”, World Health Organization said.

“This may explain why our growth of BA.2 in the US was not as great as the very big jump of BA.1 in the winter,” Gandhi said.

The level of protection can vary depending on how sick you have been, with mild cases boosting immunity for perhaps a month or two and recovery from a serious illness giving up to a year.

Question: How do existing covid-19 vaccines compare to these sub-options?

Although current vaccines and boosters are less successful in protecting against omicron than in earlier versions, they usually protect people from severe disease if they are infected with one of the new sub-variants.

“We are stable as long as she handles the vaccines we use,” said Dr. William Schaffner, a professor of preventive medicine and health policy at Vanderbilt University. “I have not seen a single field study show a significant difference between vaccine responses to omicron subvariants.

Vaccines generate cells known as “In memory cells” and are shown to recognize different options as they appear, Gandhi said. Vaccines also cause the production of T cells, which protect against serious diseasesshe said.

“While B cells serve as memory banks for the production of antibodies when needed, T cells enhance the body’s response to a virus and help recruit cells to attack the pathogen directly,” Gandhi said.

The end result is that the outbreak infection for a vaccinated individual “should remain mild with the sub-options,” she said.

The widespread spread of a relatively mild strain of the virus in the United States has probably brought dividends, providing many Americans with some immunity, whether or not they have been vaccinated. Studies show that people who were vaccinated and then infected had even greater protection than people who were vaccinated and did not receive covid.

“This Omicron family can really offer a bright side in the course of the pandemic,” Schaffner said.

Looking ahead, vaccine manufacturers are beginning to design vaccines that are specifically targeted to omicron, and some would combine a coronavirus vaccine with a seasonal flu vaccine with a single injection. But those vaccines are at an early stage, and Schaffner said he suspected they would not be ready and approved until the flu vaccination season this fall.

Whether such new vaccines represent the next step in the fight against covid will depend on the FDA and the CDC.

Question: Are there any completely new options on the horizon?

Experts agree that the only newcomers in recent weeks are growing sub-options – certainly nothing that seems as game-changing as Delta or Omicron when they first appeared.

“We still don’t know anything about what’s lurking, and the surveillance is damn aggressive,” Schaffner said.

There are estimates that more than 60% of the world’s population has been exposed to omicron and more 65% of the world’s population has received at least one dose of the vaccine, Gandhi said, “so keep my fingers crossed the development of new options will slow with this level of population immunity.”

Gandhi admitted some surprise at how quiet the horizon is at the moment, but she sees it as a positive development.

“It’s been five months since we heard about a new version that I hope reflects growing immunity among the world’s population,” she said.

KHN (Kaiser Health News) is a national newsroom that produces in-depth journalism on health issues. Along with policy analysis and surveys, KHN is one of the three main operational programs in KFF (Kaiser Family Foundation). KFF is a gifted non-profit organization that provides information on the nation’s health issues.

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