Explainer: What is the new ‘Eek’ Covid-19 mutation, and will it stymie vaccination efforts?

• Seventy per cent of Covid-19 patients tested at a Tokyo hospital last month carried the E484K mutation, nicknamed “Eek” by some scientists
• Infectious disease experts said the Eek mutation had already been discovered in other strains around the world, and vaccinations are less effective on them
• Still, experts say that it is crucial to continue vaccinating the population, whether or not there are mutations.

SINGAPORE — The Japanese government on Sunday (April 4) announced that it is expanding its emergency measures to contain a new wave of coronavirus infections amid fears over the spread of a new mutation believed to reduce vaccine protection.

This was after 10 out of 14 Covid-19 patients tested at a Tokyo hospital last month carried the E484K mutation, nicknamed “Eek” by some scientists.

But is this mutation different from other mutations such as the United Kingdom and South Africa variants? And what does this mean for Singapore’s Covid-19 response?

TODAY spoke to infectious disease experts to help to answer some of these questions.

They said that while the mutation will lead viral strains to be more resilient to the vaccine, inoculation of the population will still help to prevent such strains from further spreading.

WHAT MAKES THIS STRAIN DIFFERENT?

According to Dr Ling Li Min, an infectious disease specialist from Rophi Clinic at Gleneagles Hospital, the Eek mutation had already been discovered in other strains around the world.

Different strains have emerged in the months since the virus first started spreading around the world early last year, and the Eek mutation found in Tokyo happens to be the same mutation found in the South African and Brazilian strains, she said.

A United Kingdom study published in March said that another strain which was first found in the UK late last year has been discovered to be 30 to 100 per cent more deadly than the original variant, and more infectious.

“(The Eek) mutation appears to be more transmissible, because as we know, the South African strain has become the predominant strain in South Africa,” said Dr Ling.

She added that there are studies to show that the vaccines on the market are less effective against a strain carrying the mutation.

For example, for the South African strain, the Moderna vaccine and Pfizer BioNTech vaccine were both shown to be 62 per cent effective, compared to their 95 and 94 per cent effectiveness in relation to the original Covid-19 variant.

In contrast, the AstraZeneca vaccine is only 10 per cent effective against the mutated South African strain.

There is not yet any data available for effectiveness of vaccinations on the Brazilian strain.

Professor Paul Tambyah, who is president of the Asia Pacific Society of Clinical Microbiology and Infection, said that it is not certain if the E484K variant reduces vaccine protection. 

“The numbers in the clinical trial are small and the reality is that the E484K mutation appeared before the vaccine rollout (at the end of last year), which suggests that the mutation did not emerge as a response to vaccination,” he said.

WHY DO WE KEEP HEARING OF DIFFERENT MUTATIONS?

This is because the virus will continue to replicate as it spreads from person to person, and in replicating itself there may be some “errors” that lead to mutations.

Dr Gavin Smith, a professor in the emerging infectious diseases programme at Duke-NUS Medical School, said when a virus replicates itself, it will produce many different mutations, but only the ones that are able to further spread among populations survive.

“The fact that this mutation has popped up in different parts around the world suggests that it provides an advantage for the virus in escaping, at least partially, the immune response from a past infection, or from a vaccination,” he said.

According to infectious diseases programme leader and associate professor at NUS Saw Swee Hock School of Public Health Hsu Li Yang, the Eek mutation leads to the virus having a better attachment to its target in the human cell.

This means the virus can evade the antibodies produced by those who have been infected before or those who have been vaccinated, “to a limited extent”, he said.

“It is likely that prior vaccinated or infected persons will still be protected to a considerable extent against viruses with the Eek mutation, although infection and disease might not be completely prevented,” he added.

Not all virus mutations necessarily lead to dire outcomes, said Prof Tambyah. 

“Many viruses mutate to adapt to the human host and become more transmissible but less virulent,” he said. 

“Hopefully this virus will behave like almost all other viruses.”

HOW CAN COUNTRIES DO TO PROTECT THEMSELVES FROM DIFFERENT VIRAL STRAINS?

Still, experts say that it is crucial to continue vaccinating the population, whether or not there are mutations.

For one thing, vaccinations still have a fighting chance against some of these mutations, said Dr Smith.

“Even if (the new strains) reduce the efficacy of the vaccines, there is emerging evidence that the vaccines slow transmission as well,” he said. “You might produce less (viral shedding) and so there is lower likelihood of subsequent spread.”

Agreeing, Assoc Prof Hsu said that a potential long-term solution could be to have booster shots against Covid-19 once every few years — an extra administration of a vaccine to increase immunity against the coronavirus.

The vaccinations will also curb infection rates, giving the virus fewer chances to mutate.

“When the virus replicates less, then the chances of it developing ‘copying’ errors will also be less, giving rise to fewer mutations,” said Dr Ling from Rophi Clinic.

It is also important to not only depend on vaccinations, but also continue to abide by current safe distancing and hygiene measures, said the experts.

In order to attain herd immunity, about 70 per cent of Singapore’s population needs to be inoculated, a feat that may take until the end of the year to be achieved, said Dr Ling, giving the virus about nine months to replicate to “many, many people”.

Thus, safe distancing and mask wearing have to be abided by to prevent this intermediate spread.

“We can’t just bank on vaccinations alone,” she said.