Dec 22, 2020 05:08 PM

Zhang Wenhong: What You Need to Know About the New Coronavirus Strain

A lone passenger rides the subway in London on Sunday, the first day of the city was under the country’s strictest disease control measures.
A lone passenger rides the subway in London on Sunday, the first day of the city was under the country’s strictest disease control measures.

Zhang Wenhong is director of the infectious diseases department at Huashan Hospital in Shanghai.

Winter’s shortest day brought further darkness to the fight against Covid-19. The British health secretary, Matt Hancock, said at a press conference that a new strain of the novel coronavirus discovered in the U.K. may spread more quickly than other known variants. Authorities announced that London and the surrounding area would enter a tier-four lockdown, the country’s strictest disease control measure.

The news rapidly came to the attention of the Chinese public, many of whom expressed unease at how a country that had recently become one of the first to start administering vaccinations against Covid-19 had seemingly been overtaken once again by a new virus strain.

The BMJ, a highly respected weekly journal published by the British Medical Association, soon published an in-depth explainer by the freelance medical journalist Jacqui Wise. Here’s what you need to know about the new mutation in the U.K., including the spread of international strains and the tracking of coronavirus mutations by the China National Center for Bioinformation (CNCB).

Variations are natural and expected phenomena

Just like the D614G mutation that appeared last month, the novel coronavirus continuously mutates as it spreads. Dominant strains will inevitably appear as a natural result of biological evolution.

The new coronavirus is an RNA virus that naturally mutates as it replicates. Thousands of mutations have already appeared, but only a few may be important and change the virus in a detectable way.

Citing the Covid-19 Genomics UK consortium, Wise wrote that there are currently around 4,000 mutations in the virus’s spike protein. (The CNCB has detected some 2,900.) These mutations can be used to monitor transmission pathways and disease outbreaks, but have no inevitable causal relationship with greater infectiousness.

Currently, we can only say this newly emerged N501Y variant is related to the recent outbreak in southeast England. We do not know that the disease it causes is a more serious form of Covid-19. The adoption of stricter disease controls aims to avoid overwhelming the British health care system.

Mutations are unlikely to render vaccines ineffective

Viruses evolve through natural selection. Similarly, without the evolutionary pressure of vaccines, it is virtually impossible for nature to screen out virus strains that render vaccines ineffective. Current vaccines cause the body to produce antibodies against many regions of the spike protein. A single mutation is unlikely to reduce vaccine effectiveness.

The virus is mutating every day. Over time, more mutations will occur. The types of vaccines that have proven effective in trials will only exert evolutionary pressure on the virus after they enter the market. Where vaccines appear ineffective, we must verify them by sequencing the cases where they have failed to give protection. Once a vaccine-proof coronavirus variant is found, the vaccine can be easily adjusted in a manner akin to the seasonal flu vaccine.

On the state of China’s vaccines

People at the highest risk should be vaccinated first. This is a global consensus. Vaccination is more urgent in countries with higher incidence rates. As the world gradually opens up and vaccines spread globally, China will also inoculate high-risk groups and see the vaccination rate increase as public doubts ease. After vaccination reaches a certain point, Covid-19 will become a seasonal disease like the flu.

Have faith that China will push vaccines and disease controls in a considered and orderly way. We will come through winter’s darkest days together!

Contact translator Matthew Walsh ( and editor Joshua Dummer (

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