Health

Omicron could be ‘natural vaccine’


Research by scientists from South Africa, the US and the UK shows that antibodies produced during Omicron infection can protect people from Delta and other mutations.

If there are more works with similar results, experts say the future pandemic scenario will be less dire. Omicron could be the “natural vaccine” against the Delta wave and many previous mutations.

In the short term, Omicron could cause an increase in the number of nCoV infections, putting pressure on the global economy and health system. But in the long run, when Omicron is the dominant strain, the world will see fewer hospitalizations than the scenario of Delta raging.

“Omicron has the potential to beat Delta. This is a good thing, because we need something to live with,” said Alex Sigal, a virologist at the African Institute for Health Research in Durban and author of the new study. easily, with less disruption to life than previous strains.”

In the new study, Dr. Sigal and colleagues confirmed Omicron’s ability to evade antibodies from vaccines and natural infection.

After analyzing blood samples from people who had been vaccinated or had been infected with nCoV, they showed that antibodies against Delta and other strains were less effective against Omicron. This helps explain why many vaccinated people still have Omicron infection, but with mild symptoms. In contrast, antibodies after Omicron infection are strong enough to defend against Delta.

The work was published on December 27, 2021 and has not been peer-reviewed. According to independent experts, the results of the study are preliminary, but represent a major turning point. Carl Pearson, an epidemiologist at the London School of Hygiene & Tropical Medicine, said the findings were similar to the real situation in the UK, adding: “Omicrons emerge, grow rapidly and repel Delta wave”.

Healthcare workers prepare a dose of Johnson & Johnson vaccine at a vaccination facility in Philadelphia, US, March 2021. Photo: AP

At the beginning of a pandemic, the community rarely gets reinfected with nCoV because the first infection produces antibodies and immune cells. But since the end of 2020, new strains have appeared. Some strains, such as Delta, mutate to help the virus spread quickly. Beta has the ability to adapt and evade antibodies from vaccines or natural immunity.

Delta became popular in the summer of 2021, taking advantage of both variants. The vaccine is still able to protect users, but is no longer as effective as before. When Omicron appeared in November, it spread faster than Delta. Experts propose two theories to explain the phenomenon: the virus multiplies in large numbers or is more easily transmitted from person to person. Omicron is also contagious to vaccinated people and people who have had Covid-19.

As Omicron spreads to many countries, Dr. Sigal speculates it will create community immunity against Delta. This means that F0 infected with the Delta variant are less likely to pass the disease on to others. That competitive advantage from Omicron marked the end of the Delta variant.

Nathan Grubaugh, an epidemiologist at the Yale School of Public Health sees a similar pattern in Connecticut. His and colleagues’ research shows that the anti-Omicron antibody is more powerful than Delta, able to neutralize Delta. “Omicron cases increase exponentially while Delta cases decrease,” he said.

In the UK, people who have recovered from Omicron have high levels of antibodies, which are an effective shield against Covid-19 and corona virus pathogens in general. Its mechanism is similar to that of a vaccine. But according to research by British scientists, antibodies after Omicron infection even outstrip existing vaccines. This may be the reason why when the number of nCoV infections in the UK increases, the situation is still not considered serious.

Depending on the characteristics of the virus, Dr. Pearson proposed three different scenarios of a pandemic. Firstly, Covid-19 develops like a flu, new strains appear seasonally, overwhelming the previous ones. Second, Covid-19 is similar to dengue fever. Variants exist simultaneously, people get the disease every few years. The third brightest scenario: a dominant strain, Covid-19 becomes an easily contained pathogen. But Dr Pearson thinks this is the most unlikely scenario.

Thuc Linh (Follow Reuters, DNA India)

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