Americans can be forgiven if they have lost track of the latest variant of the coronaviruses. A new Greek-letter variant hasn't come onto the scene in almost half a year.
The most recent Greek-letter variant, omicron, has emerged in the past few months.
How different are these subvariants? Is it possible to protect someone from infections by different subvariants? How well are the existing coronaviruses vaccines doing against the subvariants?
We asked medical and epidemiological experts a lot of questions. Here is a rundown.
A: What are the subvariants? How much do they have in common?
The omicron subvariants look like an alphabet soup. The original variant was called B. 1.1.529. The initial omicron variant has subvariants such as BA.1, BA.2, BA.3 and BA.4.
Monica Gandhi is a professor of medicine at the University.
The minor-to-modest changes in these subvariants can make them more transmissible. The more transmissible the subvariant is, the higher the number following it. For instance, BA.2 is thought to be 30% to 60% more transmissible than previous subvariants.
Within a few weeks, the subvariants will be overtaken by a slightly more transmissible subvariant. The process continues.
The initial variant, B. 1.1.529, was dominant in the United States in late January. By mid-March, BA.1 began losing ground to BA.2 which became dominant by early April. According to data from the Centers for Disease Control and Prevention, another subvariant was gaining steam, accounting for 29% of infections by late April. The late wave of late 2021 has not been a factor during this time frame.
What is the severity of illness?
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The illnesses caused by omicron have been less severe than those caused by previous variant, a pattern that seems to hold for all the subvariants studied so far. Gandhi said that one analysis showed that BA.2 doesn't cause more hospitalizations than the BA.1 subvariant.
There is no evidence to suggest that the subvariants are more worrisome than the original omicron, other than a slight increase in transmissibility.
Dennis Cunningham, the system medical director of infection control and prevention at Henry Ford Health in Detroit, told NBC News that the symptoms from the omicron subvariants have been pretty consistent. There is less incidence of people losing their sense of smell and taste. It's a bad cold, a lot of respiratory symptoms, and a lot of body pains.
Will you be protected against others if you get infections by one subvariant?
Colin Russell is a professor of applied evolutionary biology at the University of Amsterdam.
Some people who had BA.1 have also gotten BA.2 according to the initial research. The World Health Organization said that 1 provides strong protection against reinfection.
The very large BA.1 surge over the winter may explain why our BA.2 surge in the U.S. was not that large.
Depending on how sick you were, the level of protection can vary, with mild cases boosting immunity for a month or two and recovery from a severe illness giving up to a year.
A: How do the covid-19 vaccines stack up against each other?
Although the current vaccines and boosters aren't as effective in protecting against omicron as they were before, they will still protect people from severe disease if they are exposed to one of the new subvariants.
William Schaffner is a professor of preventive medicine and health policy.
The vaccines have been shown to generate different types of cells. She said that the vaccines cause the production of T cells, which protect against severe disease.
T cells amplify the body's response to a virus and help recruit cells to attack the pathogen.
The result is that a vaccine breakthrough should remain mild with the subvariants.
The wide spread of a relatively mild strain of the virus in the U.S. gave many Americans some immunity, even if they had not been vaccined. Research shows that people who had been exposed to an infectious disease had more protection than people who didn't.
Schaffner said that the family of omicron could offer a bright side in the course of the Pandemic.
Some vaccine manufacturers are starting to design vaccines that specifically target omicron, and some would combine a coronaviruses vaccine with a seasonal influenza vaccine in one shot. Schaffner thinks that these vaccines won't be ready in time for the flu vaccine season.
The FDA and the CDC will have to decide if the new vaccines represent the next step in the fight against covid.
Is there any new variant on the horizon?
The experts agreed that the only newcomers in recent weeks have been incremental subvariants.
Schaffner said that there is nothing we know of that is threatening yet.
More than half of the world's population has been exposed to omicron.
Gandhi sees the quiet horizon as a positive development, despite acknowledging some surprise.
She said that they have gone five months since hearing about the new variant, which she hopes is reflective of increasing immunity in the world's population.
Kaiser Health News is a national newsroom that produces in-depth journalism about health issues. KFF is one of the three major operating programs. The KFF provides information on health issues to the nation.
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