The delta variant of Covid-19 appears to be loosening its firm grip on the United States. Since September 1, new daily cases have fallen by 50%. Hospitalizations and deaths, which lag behind new infections, are also on the decline.
The ongoing spikes in cases in countries like the UK and in highly vaccinated states like Vermont are a crucial reminder that Covid is still potent.
While there are some exceptions to the overall national decline of Covid in hotspots like Alaska, Montana, North Dakota, Wyoming, Idaho and West Virginia, some experts have estimated that – on the base of the growing number of immunities against vaccinations and natural infections – this could have been the last great pandemic wave in the country. Quite simply, the super transmissible delta variant, which is responsible for over 99% of the country’s workload and is the dominant strain pretty much everywhere in the world, lacks immune systems that are not trained to fight it.
But what appears to be the end of the pandemic may just be a respite. The rise of the Delta over a summer that once promised Covid freedom shows the vagaries of the virus and its endless virulence. As the delta recedes in some areas, it emerges in others. And with only 50 percent of the world’s population vaccinated, the potential to threaten new variants still remains.
There is an inherent unpredictability in the pandemic that is humiliating. Even though it appears that the initial delta wave peak has been reached, and the increase in vaccinations and immunity will surely contain the size and shape of future outbreaks, they do not rule out the possibility of other waves of the delta variant or some other rocking strain. this. The ongoing spikes in cases in countries like the UK and in highly vaccinated states like Vermont are a crucial reminder that Covid is still potent.
America’s herd immunity to the coronavirus is increasing day by day. Nearly 80 percent of adults have received at least one injection, and recent warrants that require vaccination for employment or require proof of vaccination for activities such as indoor meals will continue to increase that tally. Vaccines for children aged 5 to 11 are expected to be licensed soon. And at least a third of Americans have some natural immunity to a past infection with the virus.
But for a country in which the highly virulent delta variant still circulates among more than 70 million people eligible for the vaccine but still not inoculated, this immunity is not enough.
“There are still a lot of people who are susceptible to this virus, and you can’t run the game clock on this one. It will find you, ”said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. He noted that when it comes to pandemic waves, “it’s not clear why it starts or why it ends. What we can say is that immunization rates play a role in the scale of the disease. peak. “
The UK’s delta trajectory is informative and sobering. Despite a population fully vaccinated at 68% (compared to 58% in the United States) and already experiencing a delta wave that peaked in mid-July, its number of cases of Covid infections has returned to the same levels as there at three months.
The UK now has more daily infections than many Western European countries – France, Germany, Italy and Spain combined – and is once again preparing for a difficult Covid winter. The wave that peaked in July is now clearly followed by a new delta wave, although there are cases of a delta variant, called delta plus, which are also under investigation.
Likewise, the worst of the pandemic was considered to be over in Iran after experiencing a huge second wave of coronavirus in June 2020. Yet the coronavirus kept coming back. “Then they had a third push. Then they had a fourth outbreak. And the fifth push they’ve had this summer was the worst of all, ”Osterholm added. “Time shows us that we are getting waning immunity. “
Vermont, meanwhile, has the highest vaccination rate in the country, with 70 percent of the population fully vaccinated. But cases and hospitalizations are climbing. Pockets of the unvaccinated state are clearly partly to blame, but there are no obvious answers. More than anything, Vermont shows how hard it is to escape delta’s embrace.
On the other hand, any variant competing to overthrow the delta would likely have to preserve its extreme transmissibility and also acquire the ability to evade the immune system, which is difficult to achieve simultaneously.
“You need your virus to be able to bind to its receptor, but if you mutate the virus so that it doesn’t bind as well to bypass neutralization [antibody] response, then you reduce its ability to infect the host, ”explained Mark Slifka, an immunologist at Oregon Health and Science University.
That’s why it’s unlikely that Delta will be pushed from its perch by another variant anytime soon. His unmatched ability to spread has beaten all competing Greek letter strains in the ring, most recently Mu.
“Of all the outbreaks, this was the most transmissible,” said Dr. Monica Gandhi, professor of medicine at the University of California, San Francisco. But then, in an encouraging development, “the coronavirus spreads, and you have an induction of antibody responses in someone, including the nose, which protects them and makes them less likely to be transmitted.”
Indeed, the vaccines remain effective against delta. They are slowing down morbidity and mortality from the virus, as seen in the UK despite its slight increase in cases. As the number of vaccines increases relative to terms of office, new age groups are approved for jabs and oral antiviral pills, like molnupiravir, to treat patients earlier in their Covid journey and prevent hospitalization from becoming available, critical illness and death will be further suppressed.
But many uncertainties remain as to when the next wave will appear here, even if the overall disease burden is less, or how it will end. Add to this the heterogeneous nature of American cities and communities with their varying demographics, health, vaccination rates, mitigation efforts, and risk tolerance.
“The modeling that’s happening right now over four weeks is pixie dust,” Osterholm said.