It is quite clear why it is becoming more contagious. It is less clear why it is becoming less deadly.
Yesterday, the new coordinator for COVID White House, Ashish Jha, shared some rare good news about the virus. The number of cases has been rising in the northeast for almost two months. But deaths are not.
If you now look at the death rate in places like NY or MA
Decline to 0.3% (this is the number of deaths today divided by cases 3 weeks ago)
And since we are missing a lot of cases (due to home testing)
The CFR is even lower
Remember, throughout the pandemic, the CFR was closer to 1.6%
– Ashish K. Jha, MD, MPH (@ AshishKJha46) May 8, 2022
The picture is the same at the national level. Between April 1 and 27, the number of cases in the U.S. roughly doubled. Mortality halved in the same period. As of April 27, there has been almost no increase in deaths despite the fact that cases have continued to rise. In fact, we may be in the middle of a wave right now without realizing it:
– Meg Tirrell (@megtirrell) May 5, 2022
Why is COVID killing fewer people now than before?
Two obvious reasons. Almost everyone in the U.S. at this time has some form of immunity, either naturally or through vaccines, so our bodies are better prepared to face the virus. We can fight it before it gets serious, especially to those who are reinforced. Therapeutics that interfere with the course of the disease after infection are now available. Not so long ago, Pfizer’s miraculous drug, Paxlovid, was in such a shortage that immunocompromised people were gaining an advantage for it, but now it is plentiful enough that scientists complain that it is underused.
Good vaccines + good medicine = less death. But shouldn’t that mean less infection? If everyone now has antibodies, why do we see an increase in the number of cases?
Everything is in evolution, writes David Ax:
More cases, but fewer deaths, a phenomenon that epidemiologists call “separation,” has defined the evolution of COVID as we go through the third year of the pandemic. There are signs that the separation could actually become more extreme. After all, immunity leading to separation also encourages the virus to mutate more rapidly into all transmissible lineages.
Immunity is stimulated by mutants, which can increase immunity by placing antibodies against a mild infection. It is an accelerated loop of positive feedback whose products are antibodies and viral lines.
As the virus circulates among a population in which everyone has a certain immunity, the only strains that will thrive are those that are lucky enough to gain the ability to avoid a human immune response through mutation. The virus “grinds” with a genetic chance to become more transmissible even in a country where almost everyone has antibodies. But while these antibodies may not be enough to prevent infection with new strains, the knowledge of the virus that our T cells and B cells have acquired through previous exposure is clearly enough to trigger an immune response that limits severe disease. The result: Lots of transmission, not a lot of death.
For now. As Omicron continues to develop new subspecies, the feds are worried that the combination of cold weather and continuous viral evolution this winter will produce a megaval that could infect up to 100 million people. There are already Omicron vines that are more contagious than the parent strain, which in itself was one of the most contagious respiratory viruses ever seen. Something called BA.2.12.1 is now spreading to the northeast and is responsible for the recent rise in cases there. And two sub-compounds known as BA.4 and BA.5 are rising in Africa. They are worth watching because they are so resistant to the immune system that even a previous Omicron infection does not create much resistance:
A new preprint study, published before a peer review, suggests why BA.4 and BA.5 gain strength: they can escape antibodies created by previous infections caused by the first Omicron virus, BA.1, a variant responsible for a huge wave of infections that has affected many countries in December and January. They can also escape antibodies in people who have been vaccinated and have had a breakthrough BA.1 infection, although this has occurred to a lesser extent than in people who have just been infected…
“Our conclusions from this are, first, that Omicron itself is not a great vaccine, is it?” said Alex Sigal, a virologist with the African Health Research Institute who led the study. “Just because you’ve been infected doesn’t mean you have great protection from what’s to come.”
Viruses BA.4 and BA.5 and BA.2.12.1 have mutations at site 452 of their genome. This region encodes part of the virus receptor binding domain – the part of the virus that attaches to the door outside our cells. The Delta variant and some others have picked up mutations at this site. Researchers believe the changes help the virus bind more tightly to our cells and hide from the first immune defenders called antibodies that try to prevent the virus from invading our cells.
There has been no recent increase in deaths in South Africa, so perhaps BA.4 and BA.5 are just another step in the trend towards a more transmissible virus that causes less serious illnesses. Still, it leaves me wondering what that means for the next generation of vaccines. If Pfizer and Moderna switch to an Omicron-targeted vaccine, what good will that vaccine do us if BA.4 and BA.5 can break through the immunity created by Omicron itself?
Speaking of the massive contagion, America’s most famous super-expansion event reportedly continues to pile up casualties:
I have heard from several people that there are quite a number of cases from the White House Correspondents’ Dinner and that they are not reported because – you see, people – the cases are mostly * among journalists *. 🤗
It’s time to put on an emoji 👀. https://t.co/b6ue8glimx
– Jeremy Faust MD MS (ambulance doctor) (@jeremyfaust) May 7, 2022
Not reporting to journalists about the mistakes they made is an old tradition in reporting. Fauci reportedly complained behind the scenes that the White House set a bad example by allowing the WHCD to thrive when the virus is still spreading so widely, but in the end check no person infected with COVID was hospitalized there. More contagious, less serious, even at a White House correspondent’s dinner.