VIRUSES reproduce abundantly, and with imperfect fidelity, so mutations are commonplace among them. Most such mutations, though, have little or no effect on how a virus spreads or how deadly it is. And, until recently, SARS-CoV-2, the covid-19 virus, has been no exception to that rule. Regrettably, this seems to be changing…
Source: The Economist
Reprinted for educational purposes and social benefit, not for profit.
A new variant of the virus, known as B.1.1.7, is spreading rapidly through Britain, and local scientists estimate that it is about 50% more transmissible than other variants currently in circulation. The British authorities are therefore rushing into action to try to limit its spread. Those parts of the country where B.1.1.7 is most prevalent, including London, went into lockdown on December 20th. But cases have been turning up elsewhere, and more areas will be locked down from December 26th. More than 50 countries, moreover, have closed their borders to arrivals from Britain. Some parts of Europe are admitting only those who can show evidence of a recent negative test.
At the moment, only a few cases of B.1.1.7 are known from places other than Britain—though it has turned up in Australia, Denmark, Iceland and the Netherlands. Many experts think, however, that it is already circulating more widely than that. It is likely Britain rang the alarm bell first because it has a well-organised system for sequencing the genes of viral samples taken from patients. About 10% of virus-positive samples are so sequenced, compared with either about 1%, or none at all, in most other European countries. According to Thomas Connor of Cardiff University, in the past week alone more samples have been sequenced in Wales (population 3m) than in France (67m) during the entire pandemic. Similarly, one estimate suggests that America has sequenced only about 40 samples since the beginning of December, compared with more than 3,700 in Britain.
It is not yet clear whether B.1.1.7 causes symptoms that are any more severe than those induced by its longer-established cousins. Studies to answer this question are under way, but encouragingly hospital-admission data in B.1.1.7 hotspots do not imply that the new variant is making people more ill.
Researchers in Britain are also looking for further evidence that B.1.1.7 is more contagious than previous strains—and, if so, why. The two factors which currently suggest its greater contagiousness are its speed of spread and the details of its mutations.
That B.1.1.7 has spread faster than older versions of SARS-CoV-2 in those parts of Britain where infections have been rising unusually rapidly seems certain. It accounted, for example, for 62% of new infections in London in the week ending December 9th, up from 28% in early November. It has also accumulated an exceptionally large number of mutations—23 of them, only six of which are silent (meaning they make no difference to the final composition of the proteins encoded by their parts of the virus’s genome).
Yet more worryingly, both laboratory and animal studies have found that some of the 17 non-silent mutations in the new variant make it better at infecting cells, at making more copies of itself once it enters those cells, and at evading antibodies originally generated by the immune system during infections with other variants.
Perhaps the best evidence that B.1.1.7 is more contagious, though, is that those infected by it have higher viral loads—that is, they have more virus particles in their throat and nose swabs—than people infected by other variants. The role of viral load in contagiousness was, until recently, based on supposition rather than evidence. But a new study in Britain of about 30,000 infected people and their close contacts shows that the likelihood of someone with SARS-CoV-2 infecting others increases steadily with viral load.
Reinforcing this point, researchers from South Africa, which also has an efficient covid-19 genome-sequencing programme, have found that a fast-spreading variant detected there also has an unusually high number of mutations and shares one in particular with B.1.1.7. The South African variant is also linked to higher viral load, and has been suggested by researchers as a reason why the epidemic there has accelerated. Several countries have also banned travellers from South Africa.
A big worry with the emergence of B.1.1.7 and similar variants is whether they may reduce the effectiveness of covid-19 vaccinations. Several of the changes in B.1.1.7 are in the gene that encodes “spike”, a protein found on the surfaces of coronavirus particles which they use to enter cells. Spike is the target of the first covid-19 vaccines. But these vaccines stimulate immune reactions to parts of the protein not affected by those mutations. There is a broad consensus among experts that vaccines already in use against SARS-CoV-2 will be effective against the B.1.1.7 variant, at least until large numbers of people are vaccinated. At that point, however, natural selection will begin to favour mutations which evade the vaccine’s effects.
In the meantime, a lurking fear is that far stricter measures than have been employed previously will be needed to slow the spread of covid-19 wherever B.1.1.7 lands. All eyes are on Britain, where results from the current lockdown in London and other hotspots will provide, over the next couple of weeks, a rough idea of how much such lockdowns can achieve. If these measures fail to bend the epidemic curve downward, hospitals everywhere may have to brace themselves for yet another wave of covid-19 patients.
Over 40 Countries have travel bans from UK. Here is a list of countries that have imposed restrictions so far.
The EU Commission has urged member states to lift any travel bans to the UK to allow for essential journeys and to minimise trade disruption. With Brexit talks still ongoing and lorries piling up at the UK border, EU leaders said in a statement: “Flight and train bans should be discontinued given the need to ensure essential travel and avoid supply chain disruptions.” But these countries still have restrictions in place:
- France: A deal has been reached between France and the UK to reopen the border between the two countries to hauliers and some passengers from Wednesday – if they test negative for COVID. As part of the agreement, the military and NHS Test and Trace teams are to establish multiple testing sites in Kent.
- Belgium: Blocked the tunnel and airports from all passenger travel – even transit – for 24 hours from 12am Sunday.
Germany: Cancelled passenger flights from the UK until 31 December and extended its ban on air passenger flights to a ban on all forms of transport until 6 January
- Ireland: Flights to and from Great Britain, not including Northern Ireland, will be banned until 31 December, except for Irish residents and Irish-bound passengers stranded while transiting through British airports.
- Netherlands: Banned flights from Britain at least until the new year.
- Spain: Flights from the UK suspended indefinitely from Tuesday, with those carrying Spanish citizens and residents excluded. Border controls with Gibraltar, the British colony on its southwestern coast, will also tighten.
- Switzerland: Stopped foreign nationals arriving from the UK (and South Africa) and mandated quarantine for people arriving since 14 December.
- Italy: grounded flights from and to Britain until 6 January, while barring entry for anyone who has been in Britain in the last fortnight.
- Russia: will suspend air traffic with the UK for one week from Tuesday.
- Austria: no passenger flights allowed to land from Britain until the new year.
- Denmark: suspended incoming British flights until 9am Wednesday.
- Sweden: suspended all incoming travel from Britain and Denmark until further notice.
- Norway: banned incoming flights from Britain starting Monday for 48 hours.
- Croatia: slights from the UK cancelled for two days from Sunday night.
- Bulgaria: banned all flights to and from Britain until 31 January.
- Malta: stopped flights both ways without an end date.
- Finland: suspended flights with Britain, with the national carrier Finnair ceasing all UK flights for two weeks.
- Poland: stopping flights from Britain indefinitely.
- Portugal: stopping flights from Britain indefinitely.
- Hungary: stopping flights from Britain indefinitely.
- Czech Republic: stopping flights from Britain indefinitely.
- Slovakia: stopping flights from Britain indefinitely.
- North Macedonia: stopping flights from Britain indefinitely.
- Israel: initially banned flights from Britain (along with Denmark and South Africa) then forbid any foreign nationals from entering the country for 10 days from Monday.
- Oman: suspended all entry to the country by foreigners and halted international passenger flights, starting Tuesday for one week. Cargo flights are excluded.
- Saudi Arabia: paused all international passenger flights and land and sea arrivals for a week or until clearer details emerged about the COVID variant, with cargo flights and supply chains exempt.
- Iran: suspended flights to the UK for a fortnight from Monday. All Iranian planes ordered to return without passengers.
- Turkey: barred flights from Britain (as well as Denmark, the Netherlands and South Africa) for unknown period.
- Jordan: until 3 January, both direct and indirect flights from the UK fare banned.
- Sudan: banned travellers arriving from Britain, the Netherlands and South Africa, starting Monday and until 5 January.
- Tunisia: suspended air links with Britain, South Africa and Australia, from this Monday and until further notice. Anyone who has resided or transited through these countries will not be allowed access to Tunisian territory.
- Canada: halted flights from Britain indefinitely.
- United States: New York State governor intends to stop flights from Britain to the state.
- Peru: halted commercial flights from Europe for 14 days
- El Salvador: prohibited entry from Britain (and South Africa)
- Chile: direct flights with Britain barred, along with the entry of foreigners who had been in the UK for the past two weeks.
- Argentina: suspended commercial flights to and from Britain.
- Jamaica: Halted all flights coming into the island from the UK for two weeks, until 4 January.
- Grenada: Suspended all air traffic to and from the UK until further notice.
- Hong Kong: banned all flights from the UK.
- Pakistan: imposed temporary ban on travellers arriving from Britain from Tuesday until 29 December. Pakistani nationals can return home from Britain after a negative COVID-19 test.
- India: suspended flights from Britain until 31 December.
- Singapore: no flights to or from the UK from 23 December, including those in transit. Returning Singapore citizens and permanent residents can enter after a PCR test but must isolate for 14 days.
- The Philippines has banned all flights from the UK from 24 December until 31 December. All passengers who have been in the UK in the last 14 days immediately preceding arrival to the Philippines, including those in transit, are also temporarily restricted from entering the country for the same period.