Vaccine candidates likely remain effective against mutations: experts

By Leng Shumei and Hu Yuwei Source: Global Times Published: 2020/8/17 20:08:54

vaccine Photo:VCG

Chinese experts have moved to ease public concerns over the efficacy of experimental COVID-19 vaccines amid recent reports of viral mutations in many countries, including India, Japan and Malaysia, amid a rampant pandemic. 

A D614G mutation of the COVID-19 virus that is 10 times more infectious has been detected in Malaysia, media reported on Sunday,  citing Health Ministry Director-general Noor Hisham Abdullah, who warned the local community to be more careful.

The news, along with similar discoveries in other countries like India and Japan, have triggered public concern as the number of confirmed cases around the world approached 22 million as of Monday without an effective vaccine or drug. 

"It is normal for a virus to mutate in different countries and even in different areas of one country, as a virus has to adapt to local people's DNA and the local environment," Yang Zhanqiu, deputy director of the pathogen biology department at Wuhan University, told the Global Times on Monday.

If China had failed to control the epidemic, there would also be many mutations in China, Yang noted.   

A certain strain will form a new strain if more than 20 percent of its genetic information mutates, which may lead current vaccines to lose effectiveness, but the possibility is low. 

First, mutations do not necessarily affect the target site of the vaccine; second, current experimental vaccines normally cover more than one target site to ensure efficacy, Chinese experts noted, trying to ease public concerns.  

Researchers could also edit existing vaccines for new strains like the human papilloma virus (HPV) vaccine at different valences to suit different types of HPV, according to experts.

Mutations would not change the efficacy of drugs, according to Yang. 

A team of genomic researchers from two institutes identified 73 novel variants of the COVID-19 strain in Odisha, India, after carrying out sequencing of 1,536 samples including 752 clinical samples, Indian media reported on Saturday. 

On August 12, a study published by Japan's National Institute of Infectious Diseases also indicated that, since late May, a mutated version of the novel coronavirus has overtaken the European strain that was previously widespread in the country. Most of the recently confirmed patients in Japan are believed to have been infected with the virus after mutation, according to local media.

Facing increasing mutations worldwide, Chinese experts are calling for enhanced anti-epidemic measures, especially those against imported cases, as imported viruses will make the epidemic situation more complicated. 

According to previous research and media reports, a virus containing mutation Spike D614G had begun spreading in Europe in early February and soon became a dominant strain all over the world. This strain usually contains mutations that can increase transduction of the virus across a broad range of human cell types, including cells from the lung, liver and colon, but so far no evidence shows that the mutation would lead to more cases of the severe disease.

The strain has been identified in cases discovered during the Xinfadi Market outbreak in Beijing in June.

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