Expert: Insufficient vaccine effectiveness may cause virus mutation

Reporter : Zhu Ying / Editor : Mei Lan / https://www.ntdtv.com/gb/2021/01/26/a103040690.html / Direct translation

Due to insufficient supply of the CCP virus vaccine, the British government and US authorities are planning to postpone the second dose of vaccine. However, virus experts warn that this is dangerous because a weak vaccine may stimulate the harmful evolution of the virus. Once the virus mutates to produce immune escape ability, it will cause catastrophic consequences.

The United Kingdom and the United States have successively launched large-scale SARS-CoV-2 vaccination since the end of last year, but the number of vaccines supplied by pharmaceutical companies cannot meet the government's expected target. The British government decided to extend the time for the second dose of the vaccine from the original 3 weeks to 4 weeks, or even to 12 weeks. The US government also intends to follow the example of the British government. Some media said that postponing or canceling the second vaccination is becoming a new program in some countries. However, the strategy of delaying the second vaccination time of the vaccine has caused great controversy among virus experts, and many experts strongly questioned this.

According to the latest news from "Science" magazine, virologist Paul Bienias of Rockefeller University in the United States believes that if the second dose of vaccine is delayed, it may lead to the emergence of a virus with immune escape ability. Because millions of people have only partial immunity while waiting for the second dose of vaccine, a weaker vaccine may stimulate the virus to evolve in a harmful way.

Deutsche Welle's Chinese website reported that Philip Krause, head of the WHO SARS-CoV-2 vaccine working group, said that so far there is no sign that the SARS-CoV-2 is resistant to vaccines.

But at the same time, Krause wrote an article in a scientific journal to remind people: The rapid development of the CCP virus variant shows that this virus may surpass our imagination and mutate into a mutation with anti-immune ability at a faster rate as a virus strain.

Andrew Read, a virologist at the University of Pennsylvania, also warned that if a weak vaccine is used or the second injection is delayed too long, the effect of the related mechanism may be just the opposite, because in some cases, the effectiveness is not strong. The vaccine is conducive to the development of dangerous strains.

Other experts with the same views as Reid also pointed out that after the first dose of the vaccine, the person received the initial protection, but it has not yet formed a strong enough immunity. At this time, delaying the second dose of vaccine will give the virus more time to evolve in a dangerous direction, which is conducive to the mutation of a virus strain resistant to the vaccine. If such a virus encounters people who have not been vaccinated, it could have catastrophic consequences. In particular, a large-scale delay in the second vaccination is more likely to lead to such a situation.

However, other virologists believe that compared with the risk of mutation of the above-mentioned virus, the increased infectivity of the virus causes a greater risk of uncontrolled spread of the virus. They said that in the case of insufficient vaccine supply, they should choose to let as many people as possible get the vaccine first. "More than double the number of people have partial immunity, and it is better than half of the number of people have full immunity."

Deutsche Welle's report also specifically mentioned the outbreak in Manaus, the capital of Brazil's Amazon state. Three-quarters of the city’s residents were infected with the CCP virus in August last year. According to experts’ past experience, this rate is sufficient to form a so-called “herd immunity” in the local area. However, since December last year, a large number of citizens in the city have been infected with the CCP virus. This has led experts to suspect that a large number of patients may be infected with a mutated virus strain, and some mutated viruses in some people "escape" the body's immune response. Whether this speculation is correct or not is yet to be further sequenced and analyzed by experts on the samples.

At present, scientists are still testing the ability of vaccine-induced antibodies to neutralize different types of viruses, and human experiments to extend the interval between vaccination in the UK are also underway.