(Image: Mitchell Squire/Private Media

COVID-19 may be mutating too fast for our vaccine rollout to cope. One global survey found two-thirds of epidemiologists believe the first generation of vaccines will be useless within a year as the virus mutates. Australians are not likely to be vaccinated until the end of next year.

Contracts with vaccine manufacturers are for only the initial version of the vaccine — not updated versions to address new common strains. Low vaccination levels may also contribute to the rate of vaccine-resistant mutations and travel bubbles could allow people to catch and spread new strains.

How fast is the virus mutating?

Viruses continuously mutate. The Sars-CoV-2 virus mutates at about half the rate of the influenza virus. Importantly most of these mutations are very slight — if the virus mutates too much it couldn’t bind with spike proteins in human cells — and most mutations don’t affect the virus’ efficacy. Many dominant strains have been replaced and the original Wuhan strain has almost disappeared.

Of the tens of millions of COVID cases around the world, there are three key variants of concern as defined by the World Health Organisation: the UK’s B.1.1.7, South Africa’s B.1.351 — both of which have increased severity and transmissibility than previous strains — and Brazil and Japan’s B.1.1.281. But there are another six variants of interest emerging, the latest detected in the Philippines and Japan in February.

Some COVID treatments including convalescent plasma can drive mutations in a similar way to how antibiotic use can drive the evolution of bacterial superbugs. And immunisation expert Professor Robert Booy thinks easing travel restrictions as countries become vaccinated is a concern.

“The world will start sharing the viral pool,” he said, as people spread the virus on planes.

The trans-Tasman bubble, which opened today, also allows travellers able to bypass Australia’s border restrictions by leapfrogging from New Zealand to abroad (although they are subject to arrival caps when returning to Australia).

There is a silver lining: while many mutations have increased transmissibility, they often have decreased virulence or “decreased nastiness”.

“Looking at the trends over the last few months, the case fatality rate has been coming down internationally,” Booy said. “That may be also a reflection of treatment.”

Is the vaccine effective?

There is limited data about how effective each vaccine is to each dominant strain of the virus.

In February, South Africa paused its rollout of the AstraZeneca vaccine over concerns about the level of protection it offered against the B.1.351 strain — although the decision was based on limited data. Preliminary research has shown Novavax is only 50% effective against this strain, while extra doses of Moderna may be needed to have the same effect against it as original strains.

Virologist Professor Gary Grohmann, who has worked closely with the World Health Organisation and as a member of Australia’s Immunisation Coalition, tells Crikey that while the vaccines can be less effective, they always provide some level of protection.

“On that critical endpoint of hospitalisations and deaths, they will definitely have a good effect — it may not be perfect but it will be good,” he said.

“But it won’t have much of an effect on stopping people from getting the infection and spreading it still person to person.”

Grohmann says vaccines plus social distancing and restrictions is key.

Is Australia screwed?

Much like the flu vaccine, Australians are likely to require an annual booster dose. Pfizer has already flagged the need for a third shot within 12 months of getting the first two doses, along with annual boosters.

This will place even more strain on Australia’s rollout. It presents another challenge too: Australia’s vaccine contracts are only for the original version of the vaccine. Separate contracts for booster shots have yet to be arranged.

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