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Medscape Medical News Editor-in-Chief Eric Topol, MD, founder and director of the Scripps Research Translational Institute and professor of molecular medicine, has been closely following COVID-19 data since the pandemic began. He spoke with writer Miriam E. Tucker about the latest on SARS-CoV-2 variants and their impact on vaccine efficacy. The conversation serves as a follow-up to his April 13, 2021, New York Times opinion piece, in which he advised readers that “all variants are innocent until proven guilty.”
You have expressed overall confidence in the efficacy of the vaccines thus far despite the emergence of variants, with some caveats. How do you see the current situation?
The US Centers for Disease Control and Prevention (CDC) has designated five “variants of concern,” but only three of them are real concerns ― B.1.1.7, first detected in the United Kingdom; P.1, in Brazil and Japan; and B.1.351, in South Africa. Yet, all three are susceptible to our current vaccines.
The UK B.1.1.7 is the worst variant of all because it’s hyper-transmissible, so I call it a “superspreader strain.” It also causes more severe illness independent of the spread, so it’s a double whammy. It’s clear that it also causes more deaths. The only arguable point is whether it’s 30% or 50% more deaths, but regardless, it’s more lethal and more transmissible.
The B.1.1.7 is going to be the dominant strain worldwide. It could develop new mutations within it that could come back to haunt us. We must keep watch.
But for now, it’s fully responsive to all the vaccines, which is great because if we didn’t have them, we wouldn’t have gotten through this US pandemic like we have, and neither would Israel and the UK and other countries that have been able to get out of the crisis. We met the enemy and put it in check.
As for the South Africa variant of concern, B.1.351, we just got some encouraging news showing that it’s very responsive to the Pfizer/BioNTech mRNA vaccine in large numbers of people. The study was conducted in Qatar following that country’s mass immunization campaign in which a total of 385,853 people had received at least one vaccine dose and 265,410 had completed the two doses as of March 31, 2021.
At 2 weeks past the second dose, the vaccine was 75% effective at preventing any documented infection with the B.1.351 variant and 89.5% effective against B.1.1.7. The vaccine’s effectiveness against severe, critical, or fatal COVID-19 was greater than 97.4% for all circulating strains in Qatar, where B.1.1.7 and B.1.351 are most prominent.
We also know that B.1.351 is very responsive to the Johnson & Johnson vaccine and the Novavax [vaccine in development] to a lesser degree. It is the most immune-evading variant we’ve seen thus far, with the highest likelihood of providing some vaccine resistance, yet not enough to interfere with vaccination campaigns. So that’s great news.
The caveats here are that you definitely need two doses of the mRNA vaccines to combat the B.1.351 variant. Also, the AstraZeneca vaccine failed to prevent it in South Africa. However, that study was hard to judge because it was underpowered for number of people with mild infections. So, it didn’t look as if it had any efficacy, but maybe it would if tested in a real trial.
The P.1 (Brazil) variant is the second-highest concern after B.1.1.7 because it’s the only one in the United States that’s still headed up. It seems to be competing a bit with B.1.1.7 here. We know it was associated with the crisis in Brazil, in Chile, and some other South American countries. It has some immune escape, but not as bad as B.1.351. It also appears to have somewhat greater transmissibility but not as much as B.1.1.7.
With P.1, we just don’t know enough yet. It was difficult to assess in Brazil because they were in the midst of a catastrophe ― like India is now ― and you don’t know how much of it is dragged by the catastrophe vs driving it.
We have to respond to P.1 carefully. There are some good data that it does respond to the Chinese vaccine Sinovac and the AstraZeneca vaccine, and it appears to respond to the others as well, based on serum studies. So it doesn’t look like vaccines will be the worry with this variant. Rather, it could be competing with B.1.1.7 and could lead to breakthrough infections in vaccinated people or reinfections in unvaccinated people who had COVID-19. We need several more weeks to sort it out.
Although the B.1.427 and B.1.429 variants initially seen in California remain on the CDC’s concern list, I’m not worried about them.
You mentioned the current COVID-19 crisis in India, where a new variant has been described as a “double mutant,” but on Twitter you called it a “scariant.” Why?
First of all, the B.1.617 variant isn’t a “double mutant.” It has 15 mutations. It’s a stupid term, focusing on two mutations which largely have been put aside as to concern. One of them is the L452R, which is the same as one of the California variants, and that hasn’t proved to be particularly serious or concerning. The other is the 484Q, and it’s not clear whether that has any function.
I coined the term “scariant” in early February because it was a pretty clear trend. People don’t know what variants are. They know a little bit about mutations but not variants, and they’re scared. A few variants are concerning, but we keep learning more and more things to decrease the concern. That’s why I wrote the New York Times op-ed, to try to provide some reassurance, since there’s such paranoia.
Do you think booster vaccinations will be necessary? If so, will those be of the original vaccines or new ones that incorporate the variants?
As we go forward, there’s still potential for new variants that we haven’t seen yet that combine the worst of all features ― transmissibility and immune evasion ― especially since we have a world where COVID-19 is unchecked. So, we’re not out of it yet, but at least for the moment, we have vaccines that are capable of protecting against all variants.
In most people, the immune response against SARS-CoV-2 is very durable and strong and may well last for years. With the most closely related SARS-CoV-1, people still had immune responses up to 18 years later. However, some people will have less robust vaccine responses, including the elderly and the immunocompromised. If they don’t have great responses to the vaccine to start with, over time they’re likely to become more vulnerable, especially if they’re exposed to the variants with some degree of immune evasion.
I think we need to study these individuals post vaccination. A lot of people fit into those categories, including seniors, people being treated for cancer or autoimmune conditions, or post organ transplant. We could set up a prospective study to see whether they develop symptomatic COVID-19 and if so, from what ― the original strain, B.1.1.7, or the newer variants.
That’s where I think booster shots may be needed. They may not be necessary across the board, but perhaps just in these special subgroups.
Currently, at least 200 COVID-19 vaccines are in development. There will be vaccines you can inhale, room temperature mRNA vaccines, and potentially even oral vaccines.
In the near future, Novavax is close, and there will likely be a two-dose Johnson & Johnson version that has the same potency as the mRNA vaccines. There are a lot of moving parts here.
There may be a step down in efficacy from mRNA to the others, though, and that shouldn’t be discounted. All of the available vaccines so far protect very well against severe disease and death, but some are less effective against mild to moderate infections, which may then lead to long COVID. We don’t yet know whether those who get mild infection post vaccination can still get long COVID.
What do you think it will take to achieve herd immunity?
I prefer the term “containment.” It’s quantitative. If you get to an infection rate of less than 1 in 100,000 people, as they’ve done in Israel, with 0.8 per 100,000, then you have the virus in check, and there will be very little spread when it’s at that controlled rate, with no outbreaks. The US is currently at about 15 per 100,000. California is at 4. That still has to get lower.
We also need to get employers, universities, and health systems to get to the mandatory level. We haven’t done that yet. Some universities have mandated it for students, faculty, and staff. We need it in more healthcare systems. Right now, we only have a couple. We mandate flu shots, and flu is nothing compared to COVID-19. And the COVID-19 vaccine is far more efficacious ― flu shots are 40% efficacious, while these are 95%. COVID-19 is a tenfold more lethal and serious disease, and much more spreadable.
People are using the lack of full licensure by the US Food and Drug Administration ― as opposed to emergency use authorization ― as an excuse not to get vaccinated. A biologics license application takes time to approve. Meanwhile, we have hundreds of millions of doses that have been well tolerated and incredibly effective.
Another aspect to consider regarding containment is that about 110 million Americans have already had COVID-19, even though only about 30 million cases have been confirmed. Most of these people have immune protection, although it’s not as good as if they have one vaccine dose. But they have enough protection to be part of the story here of the wall against COVID-19 and will help us get through this.
That’s a silver lining of having an unchecked epidemic for the entire year of 2020. The good part is that’s helping to get us to achieve an incredible level of containment when we haven’t even been close. Right now, we’re as good as the country has been in the pandemic, but we still have a long gap to get down to that 1 per 100,000. That’s what we should be working toward, and we can get there.
Créditos: Comité científico Covid