Manaus, Brazil CNN  — 

The tense quiet outside the small hospital in Iranduba, Brazil, shattered when the ambulance rolled up.

Inside, medics give a woman CPR in an ultimately futile attempt to save her life. A hospital source told CNN she died soon after being brought inside.

In the four hours that CNN spent outside Hospital Hilda Freire on Tuesday morning, three Covid-19 patients died.

The chaos has become the norm here this month. What’s happening in this underequipped hospital, surrounded by the Amazon rainforest, is a small example of a new, massive Covid-19 outbreak engulfing northwest Brazil.

How is this happening again?

Not far from Iranduba is the epicenter of this new outbreak, Manaus. The capital city of Amazonas state often referred to as the gateway to the Amazon, its main connections to the rest of the world by plane or boat.

If the city’s name sounds familiar, it could be because it was the scene of one of the world’s worst Covid-19 outbreaks in April and May. The health care system collapsed and images of thousands of newly dug graves became emblematic of Brazil’s coronavirus crisis, its death toll now second only to that of the United States.

The current situation is worse than ever. January has proven to be the deadliest month of the pandemic in Manaus by far.

In May, 348 people were buried here, the worst month until now. Through just the first three weeks of January, that number stood at 1,333.

While genomic testing is not widespread in Manaus, scientists tell CNN that evidence suggests a new virus variant mixed with government inaction to create a tragic perfect storm.

Aerial view of an area at the Nossa Senhora Aparecida cemetery where graves has been dug in Manaus in May 2020.

A new coronavirus variant

Four epidemiologists told CNN that a new coronavirus variant, called P.1, is likely driving the new round of devastation that’s befallen Manaus.

“I’m usually not an alarmist about these kinds of things, but I’m concerned about what we are seeing in Brazil right now,” said Scott Hensley, a viral immunologist at the University of Pennsylvania.

Scientists say the new version of the virus originated in Brazil, and though there is a lot still to be learned about it, there are multiple causes for concern.

First, new data suggests it is more transmissible.

Researchers at Fiocruz, the Brazilian heath research institution, have been studying newly infected people in Manaus. Of the 90 who have participated so far in the study, 66 had infections caused by this new variant, according to Fiocruz researcher Felipe Gomes Naveca.

Though not conclusive, experts say it lends credence to the idea that this variant is more easily transmissible.

“If it has the capability of spreading more efficiently, (it’s) likely it might actually get more and more dominant,” Dr. Anthony Fauci told CNN’s Erin Burnett on Tuesday.

Researchers at Fiocruz have also documented at least one case of a person who tested positive for the new variant while still having antibodies from a previous Covid-19 infection. That might suggest people can be reinfected with the new variant, although one case is far from being proof.

“The fact that we’re seeing infections right now indicates that the virus circulating is either more transmissible, that it can evade antibodies, or a combination of both,” said Hensley.

The good news? For now, it appears current Covid-19 vaccines can still protect against the pattern of mutations seen in the new variant – though all epidemiologists interviewed said much more research was needed.

Man with oxygen tanks in Iranduba.

It’s not just the variant

To blame the latest outbreak simply on the variant would be to miss the forest for the trees. The new variant emerging is simply part of a broader system that has failed people in Amazonas state.

Start with the lack of a coordinated federal response, a hallmark of the administration of Brazilian President Jair Bolsonaro throughout the pandemic.

After the first wave, it was painfully obvious that Manaus’ health care system could not handle another such a crisis.

But as the worst days of April, May, and June subsided, the federal government did not double down on its response here to ensure that the city would never again be critically short of ventilators, medicines, oxygen, and bed space.

Instead, a sense of complacency creeped in, as leaders like Jair Bolsonaro called the idea of a second wave a lie. In November, he told his people to essentially accept the virus and not fear the virus “like a country of fags.”

Now critics are wondering if a similar complacency may have slowed the federal Health Ministry’s response to warning signs this month of a second crisis in Manaus.

Federal investigators are looking into why Health Minister Eduardo Pazuello was not quicker in sending help to the city after a spike in cases was documented in December, and then again after an oxygen supplier flagged issues in January.

“Although an increase in the number of Covid-19 cases was verified [in Manaus] in the week of Christmas 2020, the Minister of Health chose to send representatives of Ministry to Manaus only by January 3, one week after being informed of the calamitous situation,” said a report by the country’s attorney general which was submitted to Brazil’s Federal Supreme Court.

Pazuello has defended his actions, blaming the variant for a disaster he argues no one could have foreseen.

“This was a situation completely unknown to everyone,” he said on Tuesday. “It was too fast.”

The stage was set

But a basic understanding of how viruses evolve would have suggested this very situation was coming.

As lockdowns were eased toward the end of last year, businesses reopened and people filled the streets. Despite warnings from multiple experts that the virus was spreading, a more laissez faire attitude toward the virus spread in Manaus.

Pervasive was the now demonstrably false notion that Manaus’ massive first wave of Covid-19 reached enough of the population to create herd immunity.

“People started living as if we had a normal life, not using masks with lots of crowds,” said Naveca, the Fiocruz researcher. “We saw this a lot during Christmas and the end of the year.”

As CNN has previously reported, even as scientific warnings mounted, officials in Manaus and Amazonas state faced pressure – from both the public and from Bolsonaro’s own statements – to refrain from imposing strict lockdown measures.

But around the world, wherever existing strains of Covid-19 were allowed to keep circulating, the groundwork was being laid for new variants to emerge.

“The virus is having an opportunity to sort of explore all of these different genetic types and those that are favored are now being selected,” said Hensley.

Put another way, the more the virus is allowed to spread, the more chances it has to evolve and form new variants.

CNN’s Natalie Gallón and journalists Marcia Reverdosa and Eduardo Duwe contributed to this report.