A guide to help you keep track of all Omicron’s sub-variants

Two years on from the start of the COVID-19 pandemic, Americans can be forgiven if they have lost track of the latest coronavirus variants circulating nationally and around the world. We’ve heard of the Alpha, Beta, Gamma, Delta and Omicron variants, but a new one Variant Greek letter hasn’t been on the scene for almost six months.

instead, a seemingly infinite flow of “Subvariants” of Omicron has emerged in recent months.

How much do they differ from each other? Can an infection caused by one sub-variant protect someone from an infection caused by a different sub-variant? And how well do COVID-19 vaccines, which were developed prior to the emergence of Omicron, protect against subvariants?

We asked these and other questions to medical and epidemiological experts. Here’s what they said.

What are the sub-variants of Omicron and how do they differ?

The Omicron subvariants look like a soup of the alphabet of letters and numbers. It was called the original Omicron variant B.1.1.529. It generated such subvariants as BA.1; BA.1.1; BA.2; BA.2.12.1; BA.3; and the most recent BA.4 and BA.5.

“They all differ from each other by having different mutations in the spike protein“which is the part of the virus that enters host cells and causes infection,” he said dr Monica Ghandiprofessor of medicine at UC San Francisco.

Mild to moderate mutations in these sub-variants can make them slightly more person-to-person transmissible. Generally, the higher the number following “BA” in the subvariant name, the more transmissible the subvariant is. For example, BA.2 is thought to be 30% to 60% more transmissible than its predecessors.

These mutations allowed the subvariants to spread widely, only to be overtaken by a slightly more transmissible subvariant within a few weeks. Then the process repeats itself.

In the United States, for example, BA.1.1 was dominant in late January, having passed the initial variant, B.1.1.529. But in mid-March, BA.1.1 started losing ground BA.2, which became dominant in early April. By the end of April, another sub-variant – BA.2.12.1 – was gaining momentum, accounting for nearly 29% of infections, according to the data by the Centers for Disease Control and Prevention. (The delta wave of late 2021 was not a factor during this time frame.)

What about the severity of the disease?

Fortunately, diseases caused by Omicron have generally been less severe than those caused by previous variants, a pattern that appears to hold true for all sub-variants studied so far. An analysis from Denmark showed that BA.2 no longer causes hospitalizations compared to BA.1, Gandhi said.

Even the most recent sub-variants that have been discovered, BA.4 and BA.5show “no evidence to suggest it’s more concerning than the original Micron, other than a potential slight increase in transmissibility,” he said Brooke Nicholsa mathematical modeler of infectious diseases at Boston University.

Dr Dennis Cunninghamthe Medical Director of Infection Control and Prevention Systems at Henry Ford Health in Detroit, he told NBC News that the symptoms of the Omicron subvariants “have been fairly consistent. There is less incidence of people who lose their sense of taste and smell. In many ways, it’s a bad cold, lots of respiratory symptoms, stuffy nose, cough, muscle aches and fatigue. “

If you get infected with a sub-variant, will you be protected from others?

So far, with all the variants to date, the ability of the virus to evade existing immune protection “it is only partialjust like the seasonal flu, “he said Colin RussellProfessor of Applied Evolutionary Biology at the University of Amsterdam Medical Center.

While some people who had BA.1 also got BA.2, initial research suggests that BA.1 infection “provides strong protection against BA.2 reinfection,” the World Health Organization he said.

“This may explain why our BA.2 peak in the United States was not as large as the very large BA.1 peak during the winter,” Gandhi said.

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

How do COVID-19 vaccines compare to these sub-variants?

Although vaccines and boosters are not as successful in protecting against the Micron as they do against previous variants, they will generally protect people from serious illness if they become infected with one of the new sub-variants.

“We are standing still as it goes with the vaccines we are using,” he said Dr. William Schaffner, professor of preventive medicine and health policy at Vanderbilt University. “I haven’t seen a single field study showing a substantial distinction between vaccine responses to Omicron’s sub-variants.”

The vaccines generate cells known as “memory B cells” e has been shown to recognize different variations as they emerge, Gandhi said. Vaccines also trigger the production of T cells, which protect against serious diseasesshe said.

“While B cells act as memory banks to make antibodies when needed, T cells amplify the body’s response to a virus and help recruit cells to attack the pathogen directly,” Gandhi said.

The end result is that a breakthrough infection for a vaccinated individual “should remain mild with the subvariants,” he said.

The wide spread in the United States of a relatively mild strain of the virus dividends probably paid providing many Americans with some immunity, regardless of whether they were vaccinated or not. Research shows that people who were vaccinated and then infected had even greater protection than people who were vaccinated and uninfected.

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

Looking ahead, vaccine manufacturers are starting to design vaccines that specifically target Omicron and some would combine a coronavirus vaccine with a seasonal flu vaccine in one go. But these vaccines are in their early stages, and Schaffner said he suspects they won’t be ready and approved by this fall’s flu shot season.

Whether such new vaccines represent the next step in the fight against COVID will depend on the CDC and the Food and Drug Administration.

Are there completely new variants on the horizon?

Experts agreed that the only newcomers in recent weeks have been the incremental subvariants, certainly nothing that seems as revolutionary as Delta or Omicron was when they first appeared.

“There’s nothing we know is still lurking, and the surveillance is pretty damn aggressive,” Schaffner said.

There are estimates that over 60% of the world population was exposed to Omicron and more than 65% of the world population he received at least one dose of the vaccine, Gandhi said, “so I’m crossing my fingers, the development of new variants will slow down with this degree of population immunity.”

Gandhi acknowledged some surprise at how calm the horizon is right now, but sees it as a positive development.

“It has now been five months since we heard about a new variant, which I hope reflects the increase in immunity in the world population,” he said.