Pharma firms race to develop vaccines for virus variants

NEW YORK • Just weeks into the roll-out of vaccines to combat Covid-19, researchers are shifting their focus to a new class of potential shots to take on the threat posed by fast-spreading mutations of the coronavirus.

Dangerous variants identified in Africa, Europe and South America are carpeting the globe, pushing scientists in the United Kingdom and elsewhere to target multiple versions of the pathogen in a single shot and perhaps head off more lethal foes that may emerge.

A variant that arose in South Africa has already shown itself capable of partially evading defences raised by several vaccines. The country paused rolling out a shot from AstraZeneca because it offered minimal protection against mild to moderate illness caused by the mutant, called B1351.

The B117 lineage that surfaced in southern England has blunted the optimism that greeted highly-effective mRNA shots from Pfizer and Moderna late last year.

With a spreading virus comes an increased risk of more alarming mutations.

"We cannot be complacent that we've got the vaccines we need and it's just a matter of time to ending the pandemic - it's not," said Dr Richard Hatchett, chief executive officer of the Coalition for Epidemic Preparedness Innovations, which has worked to accelerate the development of Covid-19 inoculations.

Britain snapped up huge Covid-19 vaccine supplies early and became the first Western country to approve a shot. Now it is seeking to catch up with the outbreak and sustain its momentum in the next phase of the crisis, a difficult task as the virus runs rampant.

The government has announced a pact with CureVac to tackle variants, pairing artificial intelligence to predict future mutations with messenger RNA technology that can rapidly generate new vaccines.

After a once-promising partnership with Sichuan Clover Biopharmaceuticals ended and separate trials with Sanofi ran into delays, London-based GlaxoSmithKline is also working with CureVac on mutant-quelling vaccines.

The companies should be able to quickly redesign their inoculations based on the distinctive spike protein that the coronavirus uses to invade human cells, according to Dr Michael Kinch, a vaccine specialist at Washington University in St Louis. Although the spike protein has proven to be a good target, other surface proteins in the virus' envelope and membrane could turn out to be important too.

"Vaccines based on the spike protein are the first out of the door," said Dr Julian Hiscox, a coronavirus specialist and chair of infection and global health at the University of Liverpool.

The next round could add the N (or nucleocapsid) protein, whose job is to bind viral RNA, he said.

With both S and N proteins, "that's almost job done", he said.

Traditional methods that use the virus itself in a weakened or inactivated form and provide a broader choice of potential targets - like those used by some Chinese developers including Sinovac Biotech - could also play a more significant role, Dr Kinch said.

Another strategy involves including a variety of antigens, the molecules in the vaccine that provoke an immune response, he added.

Pfizer, Moderna and Johnson & Johnson have said they are starting work on developing booster shots or other efforts to bolster their vaccines. AstraZeneca and its partner Oxford aim to have a tweaked version tailored to new variants available by fall.

Pfizer's partner BioNTech has said that if their vaccine turns out to be ineffective against a new strain, they could, in theory, produce an updated shot targeting that variant within six weeks.

Some scientists, including a team at the University of Cambridge, are exploring vaccines that could protect against multiple coronaviruses to prepare for future pandemics.

Backed by British funding, the Cambridge group is developing technology that could be plugged into any platform to fight multiple variants and other coronaviruses, such as Mers or Middle East respiratory syndrome.

They are planning to start human trials in the spring.

Combinations are another avenue drug-makers are pursuing.

Oxford is launching a trial bringing AstraZeneca and Pfizer vaccines together to determine whether two shots of different products yield better results.

Russia is planning a study mixing the Astra vaccine with its Sputnik V shot.

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