The big story of the week: The promising Oxford vaccine trial hit a snag.
One of the participants in a phase 2/3 trial reportedly developed a serious spinal inflammation.
The trial, being staged in countries around the world, is now on hold as researchers determine whether the illness was caused by the vaccine – of which Australia has secured 33.8 million doses in advance of a positive trial result – or something else entirely.
On the same day, an intriguing story went largely through to the keeper: an essay, published in the New England Journal of Medicine, said that face masks may work to vaccinate people against the coronavirus.
The essay starts this way: “As SARS-CoV-2 continues its global spread, it’s possible that one of the pillars of COVID-19 pandemic control – universal facial masking – might help reduce the severity of disease and ensure that a greater proportion of new infections are asymptomatic.
“If this hypothesis is borne out, universal masking could become a form of ‘variolation’ that would generate immunity and thereby slow the spread of the virus in the United States and elsewhere, as we await a vaccine.”
The paper has inevitably prompted a combination of hand-wringing, caution and cautious optimism among researchers.
What is variolation?
Variolation was the practice of infecting people with low doses of smallpox and dates back to 1000 BC in India.
In most cases, it would induce a mild form of the disease, which would prevent the person from being reinfected.
The full-blown disease killed 20 to 30 per cent, while 0.05 to two per cent of people treated with variolation died.
So it was a relatively good bet.
But given 300 million people are estimated to have died in the 20th century from smallpox, untold thousands were killed by the radical cure.
So will this be an official strategy for COVID-19?
No, people aren’t going to be deliberately infected with small doses of the coronavirus.
The researchers – Professor Monica Gandhi and Dr George W Rutherford, from the University of California San Francisco – are making the case that some level of immunity is being obtained as a matter of course when people wear a face mask.
The evidence has emerged on two fronts:
- A growing understanding of how the virus is transmitted, and to what extent the body needs to be infected by the virus for it to develop an immune response, without tripping over into the full-blown disease. The scientists aren’t quite there yet with the latter problem – and they tend to be operating on well-supported assumptions
- A growing understanding of what protection face masks afford, and who they protect.
As The New Daily reported, a shift in the understanding of how masks work occurred about a month ago.
Initially, it was thought that wearing a mask helped other people by inhibiting the spread of the coronavirus, but probably provided little protection for the wearer.
Then a persuasive study from Professor Gandhi found that masks benefit people who wear them by cutting down the dose of the virus that they are exposed to.
This conclusion relied on the clinically unproven, but observationally supported idea that viral load – the amount of virus ingested by a person – determines if and to what extent a person will get sick.
Why herd immunity is a possibility
As we noted at the time, if Professor Gandhi was correct, the universal wearing of face masks could eventually lead to herd immunity.
In the essay, Professor Gandhi and Dr Rutherford note: “The typical rate of asymptomatic infection with SARS-CoV-2 was estimated to be 40 per cent by the CDC in mid-July, but asymptomatic infection rates are reported to be higher than 80 per cent in settings with universal facial masking, which provides observational evidence for this hypothesis.
“Countries that have adapted population-wide masking have fared better in terms of rates of severe COVID-related illnesses and death which, in environments with limited testing, suggests a shift from symptomatic to asymptomatic infections.”
Bottom line? Wear a mask.