Health

American expert says more than 3 doses of vaccine are needed to fight Omicron


Some experts support the idea of ​​injecting more than three doses of the Covid-19 vaccine, similar to the hepatitis B vaccination campaign, to boost immunity against the Omicron strain.

The Omicron strain spread at breakneck speed. Three weeks after appearing in the US, it became the dominant strain, accounting for 73% of all F0 cases, according to the US Centers for Disease Control and Prevention (CDC). Data collected from South Africa also points to a fact: Covid-19 cases will increase exponentially, putting pressure on the health system if there is no early response.

This situation led scientists to come up with the idea of ​​injecting more than three doses of the Covid-19 vaccine. In fact, Israel has adopted this strategy, injecting the fourth dose of the test group of medical staff since December 27.

Kent Sepkowitz, a physician at Memorial Sloan Kettering Cancer Center in New York, also supports this view. He believes that getting enough vaccines and booster doses is the best method to help repel the pandemic.

According to a study by the US National Institutes of Health (NIH), the Pfizer vaccine achieves about 80% protection after three doses. Preliminary data from Imperial College London on both mRNA vaccines used in the US also indicate that third dose efficacy ranges from 55% to 80%.

However, according to research by the UK Health Security Agency, the ability of the third dose of vaccine to prevent symptomatic nCoV infection will decline within 10 weeks of vaccination.

For people who received three doses of the Pfizer vaccine, the effectiveness decreased from 70% to 45% in 10 weeks. People who injected two doses of Pfizer and a booster dose of Moderna had better results. The vaccine still provides 75% protection for up to 9 weeks.

Healthcare workers administer the fourth dose of the Covid-19 vaccine at Sheba Medical Center in Ramat Gan, Israel, on December 27. Photo: Reuters

Controversy rages on over how best to respond to the pandemic. In the past, health and public health experts have repeatedly adjusted vaccination strategies to the actual situation. They once recommended a booster dose of the measles, mumps and rubella vaccine after seeing a number of breakthrough infections.

Besides, the concept of injecting three or four doses of vaccine to boost immunity is quite familiar to public health officials. For example, the US hepatitis B vaccination program. In people with a slow initial response (5% to 15% of the general population), officials recommend a second round of three doses of the vaccine to boost immunity. Thus, they have to receive a total of 6 doses of the vaccine.

Such campaigns run smoothly, without public outcry or criticism directed at major pharmaceutical companies, or the “conspiracy theory” that a breakthrough infection is a sign of vaccine failure. .

“As such, everyone needs a booster shot in the long term, until a new generation of vaccine is available. The standard vaccination schedule should be three doses of the Covid-19 vaccine for everyone, a fourth booster if needed. In short, we need to think flexibly about the concept of ‘full dose of vaccine’, thinking openly that we will have to give booster or periodic injections,” said Dr. Sepkowitz.

According to him, the coming months will be “very scary” because the number of nCoV infections is certain to increase. But in the field of vaccines, the world will receive a lot of positive news. He pointed out that the World Health Organization (WHO) has just approved Novavax’s Covid-19 vaccine. The vaccine uses recombinant nanotechnology, attacks the spike protein of nCoV, promoting the body’s immunity.

“For people who have had three doses of the vaccine, Omicron is bad news, but certainly not catastrophic,” Sepkowitz said.

The main problem lies with unvaccinated people. Quoting President Joe Biden, he said this population would experience a “winter of sickness and death”. He hopes the alarming infection of Omicron will help motivate those who are hesitant to get vaccinated, protect their own health and that of the community.

“Ultimately, the emergence of the aggressive Omicron variant teaches us a lesson, that no one can predict what will happen in the future, how and where the next variant will appear,” he said.

Thuc Linh (Follow CNN)

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