Mutant army moving fast but vaccines remain a potent weapon
A researcher works on a vaccine in Denmark. Picture: AFP
Borders closed, lockdowns were tightened and dire warnings of aggressive new outbreaks were issued. Scientists worried about the vulnerability of children and politicians agonised over shutting schools.
There was scant relief on the coronavirus front last week, as the discovery of an alarming pair of mutant strains played havoc with the Christmas plans – not to mention the fraying nerves – of Britons, South Africans and a rapidly growing number of other nationalities.
Yet a singular effort by a weary microbiologist in Texas offered at least a glimpse of hope that the mutant army of variant coronavirus strains will ultimately be defeated by science.
Of the many questions raised by the separate but similarly menacing Covid-19 variants first identified in southeast England and South Africa’s Eastern Cape province, the most worrying in the longer term was surely their impact on the hi-tech vaccines that are already being pumped into arms around the world.
Will the immunising effects of the medical marvels developed by Pfizer, Moderna and AstraZeneca be neutered by a malevolent shift in the virus’s angle of attack? Are we back to square one on vaccine development? How long must we endure the uncertainty of not knowing how effective and/or durable these or any other vaccines may prove?
At his Texas University laboratory in Galveston, Professor Vineet Menachery specialises in the shifting relationships between coronavirus infections and the immunity systems they confront. How does disease spread in the body, and why is the severity of symptoms so varied? What works and what does not in preventing infection and limiting its effects?
Menachery was already familiar with the most worrying of the 23 mutations identified by UK scientists in the new Covid variant, formally labelled VUI-202012/01 – a “variant under investigation”.
The new threat to British health spread so fast through London, it was estimated to account for almost two-thirds of all new cases in the capital at the time of its discovery. One of its mutations, labelled N501Y, has also been identified in the South African variant, which rapidly became the dominant strain in the Eastern and Western Cape provinces around Port Elizabeth and Cape Town.
The N501Y mutation occurs in the virus’s spike protein, a key transmission agent that binds itself to human cells via receptors in the respiratory system. Scientists on several continents are still battling to understand to what extent, and in what combination with other factors, N501Y accelerates transmission, makes patients sicker or helps the virus dodge the body’s immune defences.
Menachery swiftly set up a test with two variants – one containing the N501Y mutation and one without it. Bingo. Using antibodies taken from Covid patients who had recovered from the disease, Menachery found no serious difference in the combative powers of the human immune system, whichever of the two variants it faced.
The antibodies proved “just as good at neutralising virus with the mutation as without it”, he wrote in a summary of his findings last week. Vaccine manufacturers quickly chimed in with assurances their products could easily be tweaked to counter any dangerous mutations – just as the flu vaccine is modified each year to combat continuous variations in the virus.
In layman’s terms, there appears no need for panic: the longer-term vaccine outlook remains bright. It is the short term that still looks grim. Millions of middle-aged and younger Britons will have to survive the rest of winter before they can join the queue for jabs.
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