Çoronavirus variants are here. What now?
A new report from infectious disease experts provides policy recommendations on how the United States can reduce the impact of variants that have already emerged, as well as building a genomic surveillance system so that the country can better identify, track and evaluate other variants that may appear as the SARS-CoV-2 coronavirus continues to evolve.
Suggestions include maintaining policies that have been proven to reduce viral transmission, prioritizing contact tracking and investigating cases of infections caused by one of the worrying variants and building a broader and more coordinated national genome sequencing strategy. The Covid-19 package that Congress is putting together now is likely to include an influx of funds for genomic surveillance, so researchers are trying to imagine what this national system should look like.
advertising
Three variants have already emerged that, in different ways, present challenges for the United States. Variant B.1.1.7, which was first seen in the UK, is more transmissible than previous forms of the virus and, as research increasingly indicates, more lethal. Then there are P.1 and B.1.351, which were first seen in Brazil and South Africa, respectively. They seem to be better at reinfecting people who recovered from an initial Covid-19 attack. Some vaccines have also been shown to be less effective against B.1.351 and, given that they share some of their mutations with P.1., Experts fear that the same could happen with the latter.
STAT spoke with Caitlin Rivers, an infectious disease epidemiologist at the Johns Hopkins Center for Health Safety and co-author of the report, about its recommendations. Excerpts from the conversation are below, slightly edited for clarity.
advertising
Your first recommendation for dealing with current variants is to maintain policies that delay transmission. But governors or mayors are looking at a very sharp drop in cases now and, like, great, we can ease some things. Some ended mask mandates and some are allowing more activities, such as meals indoors, or reducing capacity limits at companies. Why isn’t it time for that in your eyes?
Two reasons. One, although we have declined a lot since the peak of the wave in early January, we are still well ahead of the previous two waves. So things are better, but they are not good. So for that reason alone, I would recommend continuing to keep the restrictions in place until we get countdowns of cases to a much more reasonable level.
And the second reason is the variants. At the moment, they are circulating at a very low level in the United States – it varies from place to place – but low on average. But we have seen in places where the B.1.1.7 variants take the foot, cause resurgences. And the lower we can be at the starting point if B.1.1.7 starts to establish itself, the better position we will be in the long run. We are preparing now to have a better future.
What are some of the limits of the US genomic surveillance system? Where are the bottlenecks?
We have great capacity in this country to do this job. We have a lot of sequencing capacity, we have a lot of scientific capacity for characterization. What is really missing is coordination – how to bring everything together and ensure that all that effort and information is brought together in a system that helps support our response.
The scale is also a bottleneck. There are many building blocks that we need for a successful genomic surveillance system. CDC is doing this work, private sequencing companies are doing this work, academic labs are involved in characterization, but it is not on the scale necessary to support the magnitude of the response we need. And it is not coordinated enough to make the most of existing elements.
How quickly can the country’s genomic surveillance system be strengthened? Is it something that would take too long or could some things be done more quickly?
We could be doing a lot more with what we have, because there is a lot of sequencing capacity in the United States. There is still much on the table that we could be making better use of.
The other motivation is that there are substantial funds for this in the American rescue package, and therefore it is looking forward to seeing how we could use these funds and how they could go towards building a functional system.
Based on the available data, which is limited, how do you see what is happening with the variants in the US now?
Variant B.1.1.7 is definitely more prevalent than the other two. We saw that, in the UK, this precipitated a serious resurgence that led to a blockade. That is the concern here – that it would become established and would reverse part of the progress that we are seeing.
The other two are circulating, as far as we can tell, at much lower levels, although we are not looking very closely. The biggest concern with them is the immune escape [when the virus mutates in such a way that immune protection from an earlier infection or a vaccine isn’t as robust]. So, particularly, as we look to the future, it will be very important to have a good system in place that is able to observe these and other variants and adapt our countermeasures.
Another point: there is a lot of talk now about genomic surveillance, but what I don’t hear much about is characterization. Just because you’ve identified a new variant, it doesn’t mean you know what to do with it. It is very important to imagine how to turn these sequencing results into something meaningful for public health.
So, you’re saying that if you identify a new variant that you think has some kind of impact on transmission or immunity, for example, how do you go from identifying a new variant to finding out what it means, if it means ? Is that what characterization means?
Yes, that is exactly it.
Can you explain what you are imagining what the next months will be like with the variants and cases?
The variants are a little complicated. I could see a scenario where B.1.1.7 could slow down our progress and perhaps precipitate resurgences in some communities – perhaps not across the country, because some communities have very substantial levels of population immunity, but some places may rise again. But as we go through the summer and into the next winter, this is where we want this surveillance system to come into operation. If there are variants that are showing immune escape, what we don’t want is to be unprepared and suffer another wave, because this hypothetical variant is no longer a good combination for vaccines.