In addition to reversing the Trump administration’s decision to lift bans on travel to the U.S. by non-residents who have been to Brazil or Europe in the past 14 days, the Biden administration will add South Africa to the list of banned countries.
Right now the South African variant of Covid-19 is most concerning, but this new policy will not stop it from entering the U.S.
President Joe Biden will impose a ban on most non-U.S. citizens entering the country who have recently been in South Africa starting Saturday in a bid to contain the spread of a new variant of COVID-19, a senior U.S. public health official told Reuters.
…“We are adding South Africa to the restricted list because of the concerning variant present that has already spread beyond South Africa,” said Dr. Anne Schuchat, the CDC’s principal deputy director, in an interview Sunday.
Viruses mutate. On average they usually become easier to spread and less deadly. Viruses that kill their hosts quickly don’t survive as well, and those that last inside of hosts a long time are better able to mutate.
During the course of the pandemic the SARS-CoV-2 virus has remained surprisingly stable, although the earlier D to G mutation in Europe that became dominant in the U.S. was an early change that made the virus more infectious.
Recently there have been several mutations which have caused significant concern. The U.K. B.1.1.7 variant raised alarms because it spread more quickly and became dominant in several countries. It’s in the U.S., perhaps 1% of cases but we don’t really know, and could become dominant in a couple of months.
That’s concerning for four reasons,
- more spread means more overloaded hospitals
- more spread means more deaths
- more virus in the community means greater opportunity for further mutations
- a higher reproduction rate means more people need to be infected or vaccinated to reach herd immunity
The U.K. strain isn’t the only mutation and may not be the most concerning one. Right now I’m most worried about the South African “501Y.V2” mutation. It’s named for the N501Y mutation in the spike protein. The South African and U.K. strains both share this same mutation, but this variant also contains two other changes to the spike protein that aren’t in the U.K. B.1.1.7 strain.
Since vaccines target the spike protein, changes in that protein could mitigate vaccine effectiveness. And we’ve already seen reports that the South African variant:
- isn’t responsive to antibody treatments derived from earlier versions of the virus
- could lead to re-infection (for the same reason it evades vaccines, it evades the body’s immune response to earlier variants)
We don’t know if the South African strain is in the U.S. – but that’s because the U.S. does very little genomic surveillance, there simply isn’t a lot of testing of samples to know what mutations may be present here. In late 2020 the U.S. was sequencing an average of less than 500 samples per day or less than 1/3rd of 1% of positive tests. And the CDC goal is merely to get up to around double that.
However even if it’s not, or cases here don’t become widespread or dominant, this new ban isn’t going to keep it out.
- The South African strain is no longer just in South Africa. It’s even in the U.K.. So saying ‘no travel from people that have been in South Africa’ doesn’t stop the South African strain from coming. That’s like saying Covid-19 can no longer enter the U.S. because it originated in China and we’ve banned travelers who have recently been to China.
- This doesn’t stop Americans from traveling to South Africa and back, or from stopping U.S. residents currently abroad from entering the U.S. if they’ve been to South Africa. And there are various other categories of people exempt from the ban. So many of the people who would have traveled from South Africa to the U.S. will still do so.
We don’t yet know that these new variants are more dangerous (there’s some evidence the new U.K. strain is more lethal although this is not yet clear). We don’t know for certain that any reduce vaccine effectiveness – yet. And there’s reason for optimism that mRNA vaccines at least (like those from Pfizer-BioNTech and Moderna) could adapt within a couple of months to changes in the virus.
However we need to crush the pandemic quickly because the virus has more of an opportunity to mutate further. If we can reduce the amount of virus in the community, we reduce the chance the virus mutates, in a virtuous cycle that helps end the pandemic. That’s why we need more doses of vaccines in arms quickly, and those $1.16 N95 masks can’t hurt.
(HT: One Mile at a Time)