How fast does it spread? Scientists wonder if omicron can outperform delta

When scientists scramble to understand the consequences of the omicron variant of COVID-19, one of the most important questions is whether the new version of the coronavirus can outperform the delta, which dominates the world.

World Health Organization (WHO) designated omicron on Friday as “worrying variantJust a few days after its existence was first reported in southern Africa. WHO said it is coordinating with many researchers around the world to better understand the impact on the COVID-19 pandemic and new findings are expected in “days and weeks”.

Many questions remain, including whether omicron will elude vaccine protection and cause more serious disease, but these characteristics would be far less worrisome if the new variant remains relatively contained.

Several disease experts interviewed by Reuters said there is already strong reason to believe that omicron will make vaccines less effective. Omicron shares several key mutations with two previous variants, beta and gamma, that made it less vulnerable to vaccines. In addition, it has 26 unique mutations, many of them in regions targeted by the antibodies in the injections.

Delta spread in a few months and much faster than any of its predecessors.

“So the question, really, is how transmissible omicron is relative to Delta. That is the most important thing we need to know.“Said John Moore, professor of microbiology and immunology at Weill Cornell Medical College in New York.

It is also likely to be one of the last answers, according to experts. South African authorities sounded the alarm over omicron after identifying only dozens of cases of the variant.

Scientists will keep a close eye on whether omicron cases reported in public databases start to supplant those caused by delta. This could take three to six weeks, depending on how quickly the variant travels, according to experts.

The rest of the information should arrive more quickly. In two weeks, “we will have a better idea of ​​the severity of the disease“Said the doctor Peter Hotez, a vaccine expert and professor of molecular virology and microbiology at Baylor College of Medicine.

“We are receiving different reports: some say it is a very mild disease and others (report) some serious cases in South African hospitals”He added.

In a similar time frame, the researchers said they hope to have answers about whether omicron can evade the protection of vaccines. The initial data will come from laboratory analysis of blood samples from vaccinated people or laboratory animals, analyzing the antibodies in the samples after exposure to the new variant.

“There are many labs that are actively looking to test for antibody sensitivity, and that is going to take a couple of weeks.“Said Moore.

David Ho, professor of microbiology and immunology at the Columbia university, in New York, believes that omicron will show a significant degree of resistance, based on the location of its mutations in the spike protein of the virus.

“The antibodies in the vaccine target three regions of the coronavirus spike, and omicron has mutations in those three regions ”, Ho said. “Technical experts are much more concerned than public health experts about what we know about structural analysis.”From omicron.

Others point out that older variants, such as beta, also had mutations that made vaccines less effective, but that those vaccines continued to help prevent serious illness and death. Even if vaccine-induced neutralizing antibodies become less effective, other components of the immune system, known as T and B cells, will likely compensate, they said.

“Vaccination is likely to continue to keep the patient out of the hospital”, Indicated John Wherry, director of Penn Institute of Immunology in Philadelphia.

The first field studies on the efficacy of the omicron vaccine are likely to take at least three to four weeks, as experts study the rates of so-called infections “penetration“In people already inoculated, said the doctor Michael Osterholm, an expert in infectious diseases of the University of Minnesota.

David Ho, from Columbia, commented that the fact that omicron is already spreading in the presence of delta, “which outperformed all other variants, is worrying”. But others insist that it remains an open question.

As for the specific mutations that could help omicron spread, “doesn’t seem much different from alpha or delta”Said Hotez.