Here’s why the COVID-19 surge slamming a major Brazilian city is especially troubling: public health expert

Recent headlines surrounding the COVID-19 pandemic have offered both good news and bad news. The good news: millions of people around the world have been vaccinated for the COVID-19 coronavirus. The bad news: new COVID-19 variants in Brazil, South Africa and the U.K. are even more aggressive and contagious than "traditional" COVID-19. And medical writer Dr. James Hamblin, in an article published by The Atlantic on February 1, explains why he finds Manaus, Brazil's battle with COVID-19 especially troubling.

Manaus was ravaged by COVID-19 during the spring of 2020. Now, it's being ravaged all over again — and this time, Brazil has a troubling new COVID-19 variant known among scientists as P.1 or B.1.1.248.

"Even in a year of horrendous suffering, what is unfolding in Brazil stands out," writes Hamblin, who is a lecturer at the Yale University School of Public Health. "In the rainforest city of Manaus, home to 2 million people, bodies are reportedly being dropped into mass graves as quickly as they can be dug. Hospitals have run out of oxygen, and people with potentially treatable cases of COVID-19 are dying of asphyxia. This nature and scale of mortality have not been seen since the first months of the pandemic."

According to Hamblin, the latest COVID-19 nightmare in Manaus is occurring in a "very unlikely place." Manaus was hit so hard by COVID-19 in April-May 2020 — which is autumn in Brazil — that according to medical experts, the Brazilian city should have been on the path to herd immunity.

Hamblin explains, "Manaus saw a devastating outbreak last April that similarly overwhelmed systems, infecting the majority of the city. Because the morbidity was so ubiquitous, many scientists believed the population had since developed a high level of immunity that would preclude another devastating wave of infection…. Data seemed to support the idea that herd immunity in Manaus was near."

Brazil is second only to the United States when it comes to deaths from COVID-19. According to researchers at Johns Hopkins University in Baltimore, COVID-19 has killed more than 2.2 million people worldwide — and that includes over 443,000 deaths in the U.S. and over 225,000 in Brazil. Other COVID-19 hotspots, Hopkins reports, include Mexico at #3, India at #4, the U.K. at #5 and Italy at #6.

Hamblin notes that in April 2020, "blood tests found that 4.8% of (Manaus') population had antibodies to SARS-CoV-2. By June, the number was up to 52.5%. Since people who get infected do not always test positive for antibodies, the researchers estimated that by June (2020), about two-thirds of the city had been infected. By November, the estimate was about 76%."

That's a staggering number; COVID-19 is so infectious that according to some estimates, three out of four Manaus residents had been infected by November 2020. If that estimate is accurate and 76% of Manaus residents had, in fact, been infected with COVID-19, that should be a recipe for herd immunity.

"Yet now," Hamblin writes, "the nightmare scenario is happening a second time. The situation defies expert expectations about how immunity would help protect the hardest-hit populations. By estimates of leading infectious-disease specialists, such as Anthony Fauci, when roughly 70-75% of the population is immune, there can still be clusters of cases — but sustaining a large-scale outbreak becomes mathematically impossible. Still somehow, according to the Washington Post, hospitals in Manaus that had thought they were well prepared are now overwhelmed."

According to Hamblin, "The new wave of COVID-19 cases in Manaus occurred about eight months after the initial wave. People might have lost some degree of immunity during that window. But that's likely only part of the picture…. The variant in Brazil, known as the P.1 or B.1.1.248 lineage, has a potent combination of mutations. Not only does this variant seem to be more transmissible; its lineage carries mutations that help it escape the antibodies that we develop in response to older lineages of the coronavirus. That is, it at least has a capacity to infect people who have already recovered from COVID-19, even if their defenses protect them against other versions of the virus."

With aggressive new COVID-19 variants having emerged in Brazil, South Africa and the U.K., medical experts are being asked how effective the vaccines from Modern, Pfizer and others will be against them.

"It's not yet known how many of the people currently infected in Manaus have previously recovered from COVID-19," Hamblin observes. "Early data suggest that the P.1 variant is now dominant in the city, but this does not mean the variant will take over everywhere. Each place and population is unique, and susceptibility will vary based on which variants have already spread. Still, the virus' capacity to cause such a deadly second surge in Brazil suggests a dangerous evolutionary potential."

Vaccines, according to Hamblin, will have to keep up with COVID-19's evolution in the months ahead — and the more people who are vaccinated, he stresses, the better.

"In a recursive loop, the virus could come back to haunt the vaccinated — leading to new surges and lockdowns in coming years," Hamblin warns. "The countries that hoard the vaccine without a plan to help others do so at their own peril."