We are barely a week into 2021 and already there are urgent warnings about a novel pandemic virus strain spreading surreptitiously and exponentially across the world.
This seems like déjà vu. But in a sense that’s a good thing: This is not just another chapter in the exhausting saga of SARS-CoV-2, the virus that causes Covid-19, which newly available vaccines will slowly bring under control.
Humanity wasn’t remotely prepared for our struggle with SARS-Cov-2 when it emerged late in 2019. So we lost to it.
But we are better prepared for this new enemy, called B.1.1.7, or B-117 for short.
We already understand how this new virus spreads, which public health strategies can help contain it, and how to effectively treat people infected with it. We’re already performing millions of diagnostic tests each day that can sensitively detect the new pathogen and distinguish it from our old foe.
Anyone who has already had Covid-19 is highly resistant to B-117, a variant of SARS-CoV-2. So in one respect the old virus is helping us against the new one. Most important, the new vaccines that have been developed against SARS-CoV-2 and that are being rolled out in the U.S. and several other countries around the world are likely to protect us against B-117, meaning vaccination campaigns could defeat both viruses.
Yet B-117 has two critical advantages. One is that we’re justifiably exhausted from fighting Covid-19. People may struggle to muster the energy to respond to a new viral threat, especially when the rise of the new virus is hidden in the larger sea of SARS-CoV-2 cases. The other is that cases of B-117 can rise far faster than those of our 2020 foe. In the United Kingdom, where B-117 appears to have evolved, most districts that imposed Tier 4 stay-at-home conditions kept SARS-CoV-2 cases flat only to see B-117 increase 10-fold every three weeks or so. The same pattern of exponential growth seems to have begun in Denmark.
What might this mean for the at least 32 countries outside of the U.K. with confirmed cases of B-117?
Assume that your community is using masks and distancing to maintain flat SARS-CoV-2 transmission levels, but it has detected a single case of B-117 (plus 1,000 cases of SARS-CoV-2). In three weeks, your community may have ten daily B-117 cases (plus 1,000 SARS-CoV-2 cases). In six weeks, there could be 100 cases of the novel variant (plus 1,000 SARS-CoV-2). In nine weeks, half of all cases may be B-117, and the number will continue to increase even once the spread of both viruses slows due to infection and vaccination building up immunity in the population. These estimates are meant to illustrate what can happen, but are consistent with what we know about the comparative spread of B-117 and other strains of SARS-CoV-2.
Because B-117 can grow exponentially even in communities that are keeping SARS-CoV-2 under control, the situation is extremely urgent. If we want vaccination to win this new race, we have to slow down the new virus while it’s still rare.
Step one is to find the enemy. Each week, Thermo Fisher makes 20 million TaqPath test kits capable of detecting B-117, which exhibits a pattern of “S-gene dropout” that distinguishes it from SARS-CoV-2. These kits, an equivalent of the PCR tests used to detect SARS-CoV-2 infection, and/or genetic sequencing can be used on samples that already tested positive for SARS-CoV-2 to see which of them were actually B-117. No emergency use authorization is required to further analyze positive samples.
Step two is to redirect resources to the new and faster-spreading threat. Testing and contact tracing can slow the spread of rare pathogens such as B-117, but become comparatively ineffectual when there are too many cases. Multiple models (including one developed by one of us, K.E.) show that tracing bidirectionally to find both the sources of infection as well as those exposed to it can prevent more than twice as many cases as standard methods.
This suggests that as soon as the first person is diagnosed with B-117 in a community, local contact tracers should drop everything else in order to map the complete chain of transmission of the new strain using every resource available. Veteran tracers can visit the homes of contacts to provide medical advice, take samples to be mailed to labs to be tested for B-117 with next-day results, and offer supplies to people who need to self-quarantine.
Widely publicized guarantees of legal exoneration for anything revealed in the course of contact tracing could help combat mistrust. Governments should also offer financial compensation and job preservation to exposed individuals self-quarantining at home and B-117-positive people isolating, if necessary, in publicly provided hotel rooms or other accommodations. Because this new threat remains rare in most of the world, we have a second chance to apply the testing and tracing countermeasures that helped contain the initial spread in some locations, and that faltered in many others because SARS-CoV-2 had already become too widespread.
Step three is to consider diverting doses of Covid-19 vaccines to any region with large clusters of cases for whole-community vaccination. To be clear, we have very limited data showing how well the current vaccines prevent infection or transmission of B117. Yet the data we do have suggest the effect could be substantial, as it is for virtually all other viral vaccines.
Given the tremendous importance of blocking B-117’s exponential growth early, it seems worth swiftly trying this approach, monitoring the results, and adapting as we learn how well it is working. We didn’t have this potential silver bullet last time. Now it could turn the tide.
Two other steps are needed. In the immediate term, diagnostics must be developed that can detect other SARS-CoV-2 variants of concern, such as the 501.V2 strain that has appeared in South Africa but is not yet known to have spread to the U.S. or to many other countries harboring B-117. This variant does not yet appear to be as transmissible as B-117, but questions about how vulnerable it is to the Covid-19 vaccines have not yet been resolved.
Starting now, over the next few years we must build a genomic monitoring system to detect evolutionary changes in viral, bacterial, and other pathogens that could require new measures to protect public health, and that could detect new pandemic pathogens of any provenance early enough to intervene. The need is global, so as the US upgrades domestic systems, we should be learning from the experience of countries that have been more agile in spotting new variants, such as the U.K. and South Africa, and helping others to set up their own systems.
Genomic monitoring will be a central pillar of the larger project to massively upgrade the public health information systems that failed at many stages of the current Covid-19 pandemic.
Those who are fatigued and impatient for the pandemic drama to end — a category that includes both of us — can take comfort in the fact that the light at the end of the tunnel is still getting brighter, even though the emergence of B-117 adds an extra measure of urgency. Biologically, the new virus is an evolved variant of SARS-CoV-2. Epidemiologically, it appears to be a distinct and more formidable enemy, but one for which we are far better prepared.
It’s 2021, and a different race has begun. Let’s win this one.
Kevin Esvelt is an assistant professor at the Massachusetts Institute of Technology’s Media Lab, where he directs the Sculpting Evolution Group. Marc Lipsitch is a professor in the Departments of Epidemiology and Immunology and Infectious Diseases at the Harvard T.H. Chan School of Public Health, where he also directs the Center for Communicable Disease Dynamics.