World leaders gathered at a virtual global Covid-19 summit Thursday to discuss the next steps in a pandemic that has killed approximately 15 million people to date and disrupted the lives of everyone around the world. The event coincided with the U.S. officially marking 1 million deaths from Covid, emphasizing the toll that the virus has taken and the need for continued action to reduce health risks in the future.
The summit led to a commitment for $3.2 billion in additional funds centered on global vaccine access, with additional financial commitments to support equitable access to testing and treatments as well as future pandemic preparedness. But it is notable what was not a prominent element in the financial commitments: resources and strategies to reduce exposures for the current pandemic.
If we address exposures in the wrong way, we may invest a lot of money doing things that don’t help, or we may take unnecessarily aggressive steps that have adverse societal consequences.
Of course, it is important to provide equitable global access to vaccines and treatments, so we can reduce the worst outcomes from infection. But if we don’t also invest in reducing exposures, we will have many more cases to deal with and an increased likelihood of new variants that may elude our available vaccines and treatments. And if we address exposures in the wrong way, we may invest a lot of money doing things that don’t help, or we may take unnecessarily aggressive steps that have adverse societal consequences.
This conversation needs to start with the fact that SARS-CoV-2 (the virus that leads to Covid-19) is airborne. As has been discussed elsewhere, groups like the World Health Organization were very slow to recognize that Covid-19 is predominantly transmitted through smaller aerosols rather than larger droplets or contaminated surfaces (fomites). While this may seem like a minor distinction, it has profound consequences for how you reduce exposure. If droplets and fomites drove transmission, you would be well protected with a surgical mask, and six feet of distance would be protective. You would also conclude that wiping down surfaces is a key intervention and measures like partitions in schools or workplaces are reasonable ideas. But with aerosols, small particles suspended in the air, these strategies don’t work. Aerosols can linger in the air indoors for a long time, can sneak around gaps in masks, and plexiglass partitions can actually make things worse by trapping aerosols. This is why it is not surprising that masks reduced Covid in schools but desk shields actually increased risk.
Even armed with the knowledge of how we are exposed, if we aren’t going to eliminate Covid-19 from the planet, some might ask why we should bother spending global resources on exposure-reduction strategies. A fatalistic mindset seems to have set in, especially with the increasingly infectious variants, that exposure-reduction strategies are pointless since we are all going to get the virus eventually. But this is the wrong way to think about things.
With infectious diseases, if we reduce transmission, fewer people will get infected from a given case, waves will end more quickly and many lives will be saved. An online calculator reinforces how this can work. With a standard set of assumptions, if you put 20 people in a room with poor ventilation, no filtration and no masks, the calculator says seven of them will be infected within an hour. If you improve the ventilation (outdoor air supply increasing to the recommended six air changes per hour), only three get infected. If you add masks that have a 50 percent particle reduction effectiveness (N95s are more effective) to that scenario, only one gets infected. And if you add a good HEPA filter on top, no one may be infected. The exact numbers will differ by variant and setting, but the idea is clear: If one case quickly leads to seven, things can get bad in a hurry. If no one is infected, we can get things under control faster.
The virus doesn’t care if we are tired of dealing with it.
Even if you as an individual accept the value of exposure reduction, it’s helpful for a global Covid-19 summit focused on financial commitments to center this topic. For starters, it could lead to conversations about current global supply chains for things like respirators (e.g., N95 masks) or HEPA filters. Ideally this could be coupled with financial, manufacturing and distribution commitments to ensure adequate supplies around the world, with surge capacity as needed. Global leaders could also emphasize best practices and mechanisms to share those insights. For example, the U.S. has no federally regulated standard for masks for kids, and the approach used by South Korea to inspect and certify masks for kids could be used as a template. Not all exposure-reduction strategies apply everywhere around the world or work in low-resource settings, but in any place where people spend time indoors, something can be done to reduce exposures.
While the rationale for investments in exposure reduction is clear, there are some political barriers. Many might read this as either a call for mandatory masking everywhere or for lockdowns to eliminate exposure possibilities, neither of which is politically palatable or desirable. But if exposure reduction is talked about in the right way, it may help reduce some of the hostile rhetoric.
Openly discussing effective (and ineffective) exposure-reduction strategies reinforces that public health protections are not the same as lockdowns. More broadly, we should recognize the reality that polling data shows that the majority of the U.S. public continues to wear masks at least some of the time in public. We should be focusing energy on how to get people the most effective masks possible and to allow for them to be used in more targeted and strategic ways. Also, a more holistic discussion about exposure reduction would include ventilation and filtration, which would reduce the need for masks as the only line of defense in some settings and elevate the important topic of healthier buildings.