Drugs, vaccines still work
Writing | Yan Xiaoliu
Source | “Medical Community” Public Account
The epidemic press conference in Hohhot, Inner Mongolia on October 8 once again stated that the current round of epidemic strain in the city is Omicorong sublineage BF.7. This is the first time this branch has caused a local epidemic in China.
As of 24:00 on October 7, Hohhot has reported a total of 572 confirmed cases and 1,765 asymptomatic infections in this round of epidemic. From now on, in order to prevent the spillover of the risk of the epidemic, the city’s personnel will not leave the city for the time being in principle, except for those who go out for medical treatment and other special circumstances.
Wu Qianyu, a first-level inspector of the Shanghai Municipal Health Commission, introduced at a press conference held a few days ago that the local epidemic situation in my country is still dominated by BA.5 and BA.2.76 infections.
But from a global perspective, BF.7 shows a rapid upward trend in many countries.
WHO is tracking about 200 Omicrons, according to a statement in late September by World Health Organization (WHO) chief epidemiologist Maria Van Kerkhove subfamily. One of the closely watched variants is BF.7. It has established a firm foothold in countries such as the United States, or will overthrow the dominance of BA.5.
Immune evasion or strongest
BF.7 is derived from Omicron BA.5, three generations apart. In May of this year, Belgium was the first to report the detection. So far, the United Kingdom, the Netherlands, Denmark, France, Germany, Spain, Austria, the United States, South Korea, etc. have reported.
According to Fortune, on the basis of BA.4/5, BF.7 has the RBD mutation R346T in the receptor binding domain. This means evading immunity, that is, people who have been infected with BA.5 are still at risk of contracting BF.7.
“Scientists are concerned about BF.7 because it has the same growth advantages in multiple countries and may be more disseminated than BA.5.” Fortune reported.
According to the US CDC, the number of BF.7 infections in the country doubled in the two weeks ended September 26. The short-term growth rate outpaced all other variants tracked by the CDC over the same period.
By October 8, BF.7 had become the third most prevalent strain in the United States, accounting for about 4% of all gene sequencing results. The top two are BA.5 (79%) and BA.4.6 (13%).
U.S. News & World Report says more growth in the U.S. is expected in the coming weeks for BF.7.
Peter Chin Hong, an infectious disease expert at the University of California, San Francisco, is also keeping a close eye on BF.7, saying it may be linked to most cases in European countries such as Belgium. However, due to the significant reduction in the number of virus gene sequences in the relevant countries, the latest data cannot be obtained.
The public account “Shaanxi CDC” posted on November 11 that a non-peer-reviewed study showed that BF.7 was “the most neutralizing and resistant drug evaluated so far. variant”, which exhibits “broad escape” from neutralizing antibodies.
Immunologist and founder of UK-based Cignpost Diagnostics Denis Kinane warns BF.7 could repeat summer 2021, with delta transmission causing rapid surge in cases Case.
Image description: On September 25, Marc Johnson, a well-known professor of molecular virology at the University of Missouri in the United States, posted a pedigree map of the Omikron on social media “Twitter”, saying that the mutation of the new coronavirus appeared “convergence” evolution”. /twitter@SolidEvidence
No evidence of pathogenicity
The public and the scientific community also want to know whether the virulence of BF.7 has changed.
WHO New Crown Vaccine Priority Review Expert and Deputy Director of Jiangsu Provincial Center for Disease Control and Prevention Zhu Fengcai told the “People’s Daily Health Client” that although the transmission power of BF.7 has increased, asymptomatic patients and mild symptoms Most patients.
According to the aforementioned “Shaanxi Disease Control and Prevention” article, symptoms of BF.7 infection include high fever, persistent cough, body aches, headache, sore throat, altered sense of smell, and loss of appetite. This is very similar to the infection with the early strain of Omicron.
Comprehensive media reports, there is no evidence that BF.7 is more pathogenic than the previous Omicron sublines. The author said that from the experience of many countries this year, external factors, such as vaccination status, previous infection, antibody decline over time, and medical system Burden, etc., is more likely to affect the real-world case fatality rate of the new coronavirus than the endogenous pathogenicity.
At present, the new crown treatment drugs are still effective against BF.7. Jiang Jiandong, academician of the Chinese Academy of Engineering and dean of the Institute of Materia Medica of the Chinese Academy of Medical Sciences, told the “People’s Daily Health Client” that the main target of the new crown small molecule drug is viral replicase. No mutation was found in BF.7 in the relevant drug binding target sites, so the effect on small molecule drugs should be small.
However, it should be noted that “there is data to suggest that BF.7 has a mutation in the gene encoding the spike protein. This may reduce the efficacy of Evusheld.” CDC spokeswoman Jasmine Reed told CBS Newssaid during the visit.
Evusheld is a long-acting neutralizing antibody against 2019-nCoV that can be used to vaccinate immunocompromised or immunocompromised individuals to prevent 2019-nCoV infection.
On October 3, local time, the US FDA issued a statement saying that it has added important information to Evusheld’s authorization instructions to inform health care providers and individuals receiving Evusheld that Evusheld may not be able to Neutralizes some mutant strains, which can lead to an increased risk of infection after exposure.
The epidemic may not be good this fall
“Whether you like it or not, the new coronavirus is setting off a new round of autumn epidemics.” “Fortune” published an article on October 2 that this may be caused by a variety of mutant strains.
In addition to BF.7, Raj Rajnarayanan, associate dean and associate professor of research at New York Institute of Technology, believes that BQ.1.1, BA.2.75.2 All deserve attention. The latter is the scariest of the recent variants. Its spike protein is better at binding tightly to human cells to defend against antibody attack.
In late September, a preprint published by Imperial College London and Karolinska Institutet in Sweden stated that BA.2.75.2 showed the ability to escape widespread escape, including from the original vaccine Antibody immunity established by vaccination and previous infection.
Raj Ranarayanan points out that convergent evolution is increasingly common. This refers to strains that appeared in different regions and at different times, with the same mutation. And these mutations often have evolutionary advantages that allow the virus to spread among people with different levels of immunity.
“It is not clear which strain will prevail and become the dominant strain. Our concern is not only that they may re-infections increase. As the virus evolves, some monoclonal antibody treatments have become useless , were discarded. In some laboratory studies, some neutralizing antibody therapies were found to be ineffective against the novel variant.” STAT reported.
Institute for Health Metrics and Evaluation at the University of Washington, and experts including Dr. Anthony Fauci, the nation’s top infectious disease expert, expect this round of outbreaks to begin in late October. Peak in late December or January 2023.
“The number of infected people may be nearly 100 million.” The news commentary website quoted an analysis.
“The Covid-19 outbreak appears to be transitioning from a hyperacute phase to a generalized epidemic. The current Covid-19 vaccine is not as effective at preventing Omicron infection, but is still largely Prevent serious infection.” Chang Rongshan, an expert in virology, told the “medical community”.
He said that the more people the virus infects and the more times it replicates, the greater the chance of the virus mutating and the greater the number of mutated strains. In the case of viral epidemics spread by the respiratory tract, transmission power is the most important indicator of human adaptability, and the rule is that those with strong transmission power replace those with weaker ones. According to this theory, the future colonization hosts of the new coronavirus are children and the elderly.
Chang Rongshan said that the key at the moment is that Omicron accounts for the majority of deaths among the elderly, about 90%, which is much higher than the fatality rate for other groups. Only if nearly all eligible older adults have completed 2 doses of the vaccine (and within the last 4 months), the infection fatality rate in the elderly population is likely to drop to influenza levels, the most common seasonal epidemic. If the vaccination rate of the elderly population is lower than 80%, the so-called “new crown is close to a cold” argument is not valid.
References:
[1]BF.7 could be the next dominant COVID variant.Here’s what that would mean.salon
[2]From BQ.1.1 to XBB and beyond:How the splintering of Omicron variants could shape Covid’s next phase.STAT
[3]What to know about COVID variants BA.4.6,BF.7 and BA.2.75,now growing nationwide.CBS News
[4]WHO warns ability to identify new Covid variants is diminishing as testing declines.CNBC
[5]Things about the Omicron variant strain BF.7. Shaanxi Disease Control
[6]‘The tools are getting picked off’:An ever-mutating mix of COVID variants means fewer and less effective treatments this fall.Fortune
[7]FDA releases important information about risk of COVID-19 due to certain variants not neutralized by Evusheld.FDA
Source: Medicine
Proofreading: Zang Hengjia
Editor in charge: Tian Dongliang
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