Does wearing a mask decrease the severity of COVID-19?
A rough few months are ahead of us, but we might actually get a vaccine.
Image courtesy Pixabay. CC BY 3.0
Hello, friend!
How are you? I have lots to discuss this week, so I’ll get right to it.
We are in for a rough few months in the Northern Hemisphere. SARS-CoV-2 did not go away in the summer, but it certainly is surging in many countries as human activities move indoors, temperatures drop, and humidity falls— all factors thought to be conducive to transmission. A few days ago, Dr. Tony Fauci, director of the National Institute of Allergy and Infectious Diseases told The New York Times, “It’s almost an exponential curve... I think that December, January and early February are going to be terribly painful months.”
Around 50 million people are expected to travel for Thanksgiving in the United States. Meanwhile, the Centers for Disease Control is pleading with Americans not to travel. Whereas in early March, transmission was occurring mainly in a few hotspots; in November, spread is happening everywhere in the U.S. How will we support the disadvantaged and the vulnerable? Will we listen to the healthcare workers who are sick, depleted, and mentally vulnerable from dealing with the virus for nearly a year now? How will we get through the next few months? Some form of financial support that allows people to stay at home and businesses to remain viable is necessary. Unfortunately, it is also unlikely to occur.
The United States has already lost over 250,000 people to the virus. That is the equivalent of a Toledo, Ohio. Imagine if a great American city had been wiped off from the map by another other means. Now, it is a Toledo. Soon it will be an entire Orlando, and then an entire Cleveland, and then all of Minneapolis. Yet, the nation remains fractured and many still in denial. “It’s not that bad,” they say.
The good news is we will have vaccines.
There is good news this week. We will have multiple COVID-19 vaccines.
I won’t belabor the details here. I wrote a 2000-word piece about vaccines for Livemint which you can read here. This is a follow-up to a similar piece I wrote for the same outlet in late May in which I expressed cautious optimism that we would have successful vaccines.
The piece that came out this week is comprehensive, but there are a few other details I’d like to mention. There have also been a few developments since I wrote it:
Pfizer’s vaccine completed interim phase III trials and is about 95% effective. Importantly, it is also very effective in people above 65— those who need the vaccine the most because they are at risk of the worst outcomes of COVID-19.
Both Pfizer’s and Moderna’s vaccines are being examined for their ability to stop symptomatic disease, not infections. AstraZeneca and Oxford University’s vaccine on the other had is also designed to check for infections. Earlier this week, results of the phase II trials of this vaccine were published in The Lancet. While this vaccine is a little behind the two RNA vaccines by Pfizer and Moderna, the data look good. It seems to be safe and elicits an immune response, especially in elderly people
In India, Bharat Biotech/ICMR’s Covaxin has started enrolling 26,000 participants in Phase III trials, so its moving along quickly too. This is well-known vaccine technology, only a few months behind the frontrunners.
China's Sinovac appears to be safe in Phase Il clinical trials, but the vaccine also seems to generate lower levels of protective antibodies compared to recovered patients or to Moderna or Pfizer vaccines. This vaccine is also in Phase III trials now.
Herd immunity after infection as a strategy refuses to go away.
Every few days someone says, “Well, actually herd immunity is the best strategy”.
Inaction is not a strategy. Experts have addressed this much better than I have, but with a 66% threshold of infections needed and perhaps a fatality rate of 0.3%, we are looking at large numbers of infections and deaths if we led the virus run wild.
Ultimately these discussions of herd immunity dance around the fundamental question- “how many deaths will we accept as a society as a result of inaction?”
Personally, I am uneasy putting a price on millions of human lives for a largely preventable and soon-to-be vaccinatable disease.
Does wearing a mask decrease the severity of COVID-19?
This is a question I’ve pondered myself, been asked by many others, seen in the scientific literature, and also in the popular press. It even found mention in the most prestigious medical journal in the world.
The idea is something like this. Masks reduce the number of virus particles that enter a person’s upper respiratory tract. They can prevent infections. But even when infections occur, can they reduce the severity of COVID-19 much like a vaccine might?
At it’s simplest what this question is asking is another question: is there is correlation between the number of virus particles that enters someone and the severity of their disease? Early on, it was certainly hypothesized to be the case based on the observation that many seemingly healthy young doctors were getting very sick and dying from COVID-19. It was thought to have to do with the amount of virus they were being exposed to in high risk-setting.
But shortly after the Perspective was published there were two letters that disputed this notion in the same journal. The two letters pointed out that so far there is no evidence that there is a correlation between infectious dose (which we don’t know yet for SARS-CoV-2) and severity.
The first letter stated it clearly—
Masks are used primarily to reduce SARS-CoV-2 transmission rather than reduce the dose of infectious particles or mitigate the severity of Covid-19.
The second letter was even more direct in pointing out how SARS-CoV-2 may be unlike certain other viruses like influenza where there is more of a correlation.
This virus does not appear to follow a classic dose–response relationship (i.e., the lower a viral inoculum exposure, the less severe the disease).
So in summary, there is no actual evidence that mask wearing reduces the severity of COVID-19 symptoms.
Stay safe and mask up. You’re doing it to prevent transmission.
Predicting the pandemic
I want to share a short passage because it rings true even today. One of the leading microbiologists of the previous century, Joshua Lederberg wrote this in an article published in Social Research in 1988 at the height of the AIDS epidemic—
In other news…
A new monkey has been discovered that lives in the remote forests of Myanmar. Unfortunately, there are only around 200 left on the planet.
Researcher’s are studying Europe’s rarest fish. There are perhaps only dozens left and they all live in one specific part of a river in Romania.
Also, I announced via Twitter that I’m writing a book on COVID-19 which should be out in February.
I welcome your ideas and comments on what you’d like to see in this book.
Take care,
Anirban
If you like this post, please share it.
If you’re not a subscriber, please do enter your below to get future posts directly in your inbox.
Wonderful, informative read as usual. So wearing a mask is no guarantee against getting infected ? Am I right in my understanding? Then it makes scenario even more scary.
Ahmedabad is badly affected at the moment. And once again we are under complete lockdown for next 60 hours. They call it curfew to soften the blow. Hospitals are full and people are rushed to other towns for treatment. What surprises me is that people who has never gone out (elderly) since March, have survived on home deliveries, don't allow anyone inside their home are positive. How is it possible? Does it mean surface contamination is a strong possibility?
How to protect aged parents in such a scenario is a constant worry. How to protect oneself when neighborhood is infected?