Sunday, January 17, 2021

The virus mutates

The Boston Globe sent out a flash bulletin, clearly intended to worry its readers: “State health officials Sunday announced the first case of a more transmissible COVID-19 variant involving a Boston woman who developed symptoms after returning from the United Kingdom earlier this month. The woman, who is in her 20s, had traveled to the UK and became ill the day after she returned to Massachusetts, the department said.”

Be afraid. Be very afraid! Or not?

A key point to remember is that viruses mutate, particularly RNA viruses like the coronavirus and influenza virus. You are urged to get an annual flu vaccination not because your immunity has disappeared since last year’s shot but because the virus that circulates each winter is usually different than the one infecting people the prior year.

Mutations occur frequently; whether they become the prevailing strain depends on whether they give the mutated virus an advantage over the existing strains. Mutations that allow the virus to spread more easily, to reproduce faster or to be harder for the host immune response to destroy will have a selective advantage and soon become the dominant strain. Early in the pandemic, a mutation in the part of the viral RNA coding for the spike protein emerged and soon became the major strain. This was later found to be due to its higher transmissibility. The outbreak in Danish mink was due to a mutation that allowed the virus to better attach to receptors in the animal’s respiratory tract.

The most recent concern has been a new variant, called B.1.1.7, that appeared in the United Kingdom and which rapidly became common there. By the end of December, this strain had gone from undetected to causing 28% of all cases in the kingdom. Its “selective advantage” is clear: it spreads 56% more rapidly than the original strain. Similar but different mutations have been found in South Africa and Brazil, but as of this date seem confined to those countries.

The “UK strain,” however, has been detected in small numbers in at least 10 U.S. states as of Friday according to the CDC – and now 11 per the Globe report.

First the good news: this strain, while it spreads more rapidly, does not appear to cause more severe disease. Another piece of good news is that small studies done by Pfizer found that the neutralizing antibodies produced by their vaccine work on the B.1.1.7 variant virus.

The bad news is that because this variant spreads more easily, it is likely to become the dominant strain in the U.S. by March, and the increased transmissibility may lead to many more cases.

What does that mean for us? It adds urgency to the need to get as many people vaccinated as possible, and it means we cannot let down our guard. Basic hygiene measures: masks, social distancing, isolation and quarantine and hand washing must be maintained until a large majority have been vaccinated. So, don’t be afraid, but be sensible and cautious.

Prescription for Bankruptcy. Buy the book on Amazon