What COVID response can learn from TB
One of the oldest diseases in the world can help us fight one of the newest
Last week I pointed out that our response to COVID isn’t evolving. We keep focusing on masks, vaccines, and testing - even though the approach isn’t working. Even if people were willing to get them, our vaccines can’t keep up with variants. People keep abandoning masks. And testing is just a disaster. I suggested we look at Tuberculosis for a model of what we can do about COVID other than mask, test, vaccinate.
TB is not a viral infection. It’s bacterial. But TB has a lot in common with COVID. It’s transmitted through the air, it has a vaccine that’s less than 90% effective at preventing infection, and it has a knack for rapid mutation. It’s also a disease we are doing a decent job of fighting. Not a perfect job, but decent. The global prevalence of tuberculosis falls about 2% every year. Not as fast as we want, but a disease we’ve got under control. (1)
What can we learn from TB?
Mostly, we can learn how to stop infection without requiring human behavior change. Masks, vaccines, getting tested, these all need people to do something. Getting people to take action, or do something differently - that’s always hard. Possible, but slow and difficult. It’s just human nature.
What about the infection control you can build into your infrastructure? There are two big pieces:
Airflow
We now know that COVID is transmitted primarily through the air. Thus the need for masks. But masks aren’t the only thing we can do to slow down airborne transmission. TB hospitals and care facilities pay serious attention to airflow to prevent transmission of the infection. Sunlight kills TB bacteria - just like it kills coronavirus. Supporting air turnover - getting air outside - as often as possible can help reduce transmission of COVID.
In the US, most of our HVAC systems are designed to retain air indoors by default. It’s energy efficient to capture your cooled or heated air instead of letting it escape and having to heat or cool more air. But trapping the climate controlled air also recirculates pathogens. However, HVAC systems also have settings, and you can set them for maximum air exchange. We should all have our HVAC set to maximum air exchange, and look for other conservation choices to offset the energy use impact.
We should also be designing new buildings - and new HVAC systems - to maximize air exchange and reduce re ability of pathogens to recirculate. If you want to go way down this rabbit hole, I recommend part one of this manual on using airflow to prevent TB infection from spreading.
UV lights
Another tool we can steal from TB facilities is the use of UV disinfecting lights. We’ve known that certain kinds of artificial light can kill germs since the early 1900s, and germicidal UV lights have been used in tuberculosis infection control since the 1950s. It’s a highly effective way of killing TB bacteria in the air. Harvard medical school has an excellent set of resources on UV light and TB disinfection if you’re interested.
These lights can also kill COVID. There is a logical mechanism of action, there have been individual tests, and we have the research data to prove it. More research. And the UV wavelength that’s best at killing COVID is also the safest for humans. We should be using these lights in every crowded building in the world.
The last thing to learn from TB actually is about changing people’s behavior, but in a different kind of way.
TB care and treatment is free
That’s right. As far as I know, in every country in the world, tuberculosis care and treatment is free if you can’t afford it. TB is highly infectious, and once people are getting proper treatment, they stop being infectious. So we want people to be diagnosed with TB and then get care as fast after their infection as possible - not just for their own sake, but for the protection of other people. The biggest obstacle to getting health care is always money. So TB care and treatment is free.
If we want people to get tested for COVID and get better quickly, COVID care needs to be free. All of it. Tests should be free. Paxlovid should be free. Vaccines should be free. Staying home and resting instead of going to work should be free. (that would be employers offering enough sick leave or government payments for COVID recovery time.) All of these things are very expensive to the individual people who need them the most, yet low cost on a government level.
If people recovered better from COVID and stayed home instead of spreading it, it would make up for the cost of PCR, RATs, Paxlovid and sick leave pretty fast. I’m not an economist but I am quite confident that model would work.
Test, vaccinate, and mask is working a little. Air flow, bright lights, and money could work a little more. In a problem as large as pandemic, every layer of protection matters.
(1)We don’t have a good global prevalence for COVID because so many countries gave up on tracking community cases. All we can really track is hospitalizations now.