The virus that causes COVID-19 is evolving, and it’s complicating our efforts to end the pandemic.
By Bill Gates
I’ve spent a lot of time over the last year meeting with colleagues at our foundation and around the world about ways to test for, treat, and prevent COVID-19. In recent months, the experts in those meetings are increasingly asking the same question: How will new variants impact our efforts to end the pandemic?
The world has come a long way in the fight against COVID-19, but new variants of the virus could threaten progress we’ve made over the past year. Here are five things you should know if you want to understand how variants are (and aren’t) complicating the pandemic.
1. If you’ve ever gotten a flu shot, you’ve already dealt with a virus variant.
Viruses evolve all the time. Unless you work on infectious diseases, the idea of a “variant” might seem new and scary—but there’s nothing particularly unusual about them. Influenza’s ability to mutate quickly (I’ll talk more about this in the next section) is why we get a new flu shot every year. We need to update the vaccine annually to keep up with constantly shifting flu virus strains.
To understand why the virus that causes COVID-19 is changing, you need to understand how it works (or spreads) in your body. The coronavirus—like all viruses—has only one goal: to replicate itself. Every time the virus invades your cells, it tricks the cell into following the instructions encoded in its RNA to make more copies of the virus.
When the cell is making a new virus, it has to copy those instructions. If you’ve ever had to take a typing class in school, you know how hard it is to retype something without making a mistake. The code for the virus that causes COVID-19 is around 30,000 letters long. That’s a lot of opportunities to mess up—which the coronavirus often does.
Most mistakes lead to a virus that either is functionally identical or can’t replicate. But every once in a while, there’s a change that makes it easier for the virus to infect people or evade the immune system. When that change starts to spread through a population, a new variant emerges.
2. We’re seeing the same mutations pop up again and again. That may be good news.
All viruses evolve, but not all viruses evolve at the same rate and in the same way. Some, like the flu, change rapidly. Others mutate slowly. Fortunately for us, SARS-CoV-2 is in the latter camp. It mutates about half as fast as the influenza virus.
I know it feels like new variants are popping up all the time right now. That’s because there is so much virus circulating around the world, giving it more opportunities to change. Once case numbers go down, I suspect we’ll see new variants emerge much less often.
Compared to influenza viruses—which are made up of eight genetic segments that can be rearranged in lots of different ways—the coronavirus is a much simpler virus. The most notable mutations we’ve seen so far have happened in the same spot: the spike protein that sticks out of the surface of the virus.
That spike protein is the key to COVID’s spread. Its shape is what enables the virus to grab onto human cells. If the spike protein changes just a little, it might bind with cells more effectively (which makes the virus more transmissible) or become harder for the immune system to target (which makes people more susceptible to it). But if it changes too much, the virus can no longer gain the entry that’s key to its lifecycle.
That limited capacity for change may explain why we keep seeing the same mutations appear in different places rather than lots of distinct variations. Both B.1.1.7 (which was originally detected in the UK) and B.1.351 (which was first found in South Africa) evolved independently, yet they share a number of the same mutations. There’s clearly something about these specific mutations that makes them more likely to succeed than other changes.
Some experts think we may have already seen the most concerning mutations that this virus is capable of. But COVID-19 has surprised us before, of course, and it could surprise us again.
3. The virus is changing, but the path to ending the pandemic remains the same.
For the last year, public health experts have been repeating some form of the same message: we need to contain COVID-19 as best we can until the vaccine is ready and available for everyone.
The good news is that many of the vaccines being used today appear to prevent severe disease, even from the new variants. This is a tribute to how effective the vaccines are in general. We still need a lot more data about how effective every vaccine is against the different variants, but many of the early numbers are reassuring (especially out of Israel, where many people are already vaccinated and the B.1.1.7 strain is dominant).
The big question now is whether we need to update the vaccines to target the variants. Regulators and drug companies are working on a modified vaccine that could be out in a couple months if it’s deemed necessary. Here in the United States—where the majority of people will likely be vaccinated by the end of the summer—some people may end up getting a booster shot that protects against additional strains.
For now, the key is to keep following best practices. The best way to prevent new variants from emerging is by stopping transmission of the virus altogether. If we remain vigilant about social distancing, wearing a mask, and getting vaccinated, we will bring the pandemic to an end much sooner.
4. Variants make it even more important that vaccines are made available everywhere.
COVID-19 anywhere is a threat to health everywhere. That’s true with the original virus, and it’s true when it comes to variants.
The more the virus that causes COVID-19 is out there in the world, the more opportunities it has to evolve—and to develop new ways of fighting our defenses against it. If we don’t get the vaccine out to every corner of the planet, we’ll have to live with the possibility that a much worse strain of the virus will emerge. We could even see a new variant emerge that evades existing vaccines altogether.
No one wants that to happen. The best way to make sure it doesn’t is by getting the vaccine out to everyone who needs it, no matter where they live. That’s why our foundation is working with governments, vaccine manufacturers, organizations like CEPI and Gavi, the Vaccine Alliance, and others to deliver COVID-19 vaccines to low-income countries through an initiative called COVAX.
COVAX recently announced that it’ll be able to deliver 300 million doses by mid-2021. That’s great news, but the world is going to need a lot more if we’re going to truly stamp out the threat of COVID-19. I hope rich world countries continue to support COVAX’s work, even as life starts to get back to normal in some parts of the world over the summer.
5. We can do better next time.
Virus variants are inevitable. If we ever find ourselves in a pandemic scenario again where a pathogen is spreading around the globe, we should expect to see it adapt to survive our attempts to stop it—just as we saw with COVID-19. I hope the difference next time is that we’re better prepared to spot these variants earlier.
The key will be genetic sequencing in combination with better disease surveillance. Right now, if you test positive for COVID-19, there’s a possibility that your test sample gets selected to be sequenced. This lets researchers see the exact 30,000 letter code that makes up the virus’ RNA instructions. That code gets uploaded to a database, where a computer compares the virus in your sample to all the other strains in circulation. . If you have a new strain that’s starting to pop up over and over in your area, scientists can compare the sequence data to transmission, death, and hospitalization rates to see if there’s need for concern.
Researchers need to take a systematic approach to catch variants early. Some experts think we need to sequence at least 5 percent of all test samples to get an accurate picture of how a pathogen is mutating—although sequencing a large number of samples alone isn’t enough. The UK has analyzed nearly 8 percent of its tests and linked that data with their surveillance capabilities, which helped them see that B.1.1.7 was spreading much faster and was more lethal. South Africa was able to quickly see how vaccines worked on B.1.351 by comparing results from clinical trials there to sequenced data.
The tools we’re putting in place to monitor variants in this pandemic will prove invaluable long after the worst of COVID-19 is behind us. Widespread sequencing should be part of any plan to prepare for the next pandemic. If you’re doing enough sequencing and comparing that data with other measures, you can see concerning variants when they first emerge. The earlier you identify a change, the more time you have to study it and, if needed, to tune vaccines and therapeutics to address any changes that have taken place.
There’s no doubt that variants complicate our efforts to bring an end to this pandemic. Even once the worst is behind us, we’ll need to remain vigilant. Fortunately, we know what we need to do to stop them from emerging. For now, the best thing you can do to protect yourself is to follow public health guidelines and get vaccinated as soon as you’re eligible.
