Researchers investigated the ratio of Covid cases to deaths in Brazil last month and found it surged in young people.
Even though the numbers of cases across the country were declining the number of people aged 20 to 29 dying of the disease rose three-fold, they noticed.
And the proportion of people dying of coronavirus between the ages of 30 and 60 doubled.
Academics said the data ‘suggest significant increases in case fatality rate in young and middle-aged adults after identification of a novel SARS-Cov-2 strain circulating in Brazil’.
The variant referred to in the paper is known as P1 and has been spotted in 27 people in the UK already. It has mutations that seem to make it spread faster, infect people who have already had other strains of the virus, and it may be more deadly.
Scientists said the discovery should ‘raise public health alarms’ about the variant and vaccines should be rushed out to stop the mutant strain.
One major factor not accounted for in the study is the fact that Brazilian hospitals were overwhelmed with Covid patients in February, which may have made survival less likely for people with the disease.
The researchers admitted it was ‘difficult to distinguish’ whether the new variant or ‘pressure on hospitals’ was to blame but did not factor it into their numbers.
But they insisted the data, which came from the state of Parana, ‘coincided with a steady two-month decline in overall cases’.
The study found that Covid death rates increased dramatically in some age groups in February, rising most from 0.04 per cent to 0.13 per cent in people in their 20s (yellow) and from 0.43 to 0.9 per cent in people in their 40s (green)
Hospitals in Brazil were overwhelmed by Covid patients in February as the country grappled to get its second wave under control (Pictured: A man in hospital in Baaru, Sao Paulo)
‘The reasons for the sudden rise in CFR [case fatality ratio] are not entirely clear,’ wrote the researchers, led by the Federal University of Paraná’s Professor Helena Santos de Oliveira. Academics from Cincinnati in the US and Verona in Italy were also involved in the study.
‘During a surge, even in well-designed clinical studies, it may be difficult to distinguish between truly increased pathogen virulence versus increased pressure on hospitals, acute care beds and other healthcare resources, thus resulting in poorer clinical outcomes as the primary driver of increased mortality rates.
‘However, while it may be reasonable to assume that increased transmissibility of a novel strain may have resulted in overburden hospital system and healthcare resources, the rise in CFR actually coincided with a steady two-month decline in overall cases in the state of Parana.’
The study, published online at medRxiv, said that 70 per cent of Covid cases in the Brazilian state of Parana were caused by the P1 variant.
It did not link the P1 strain to the patients who died — but the timing of the surge in death rate and the emergence of the variant suggested a link.
The researchers found the Covid death rate for people in their 20s was 0.04 per cent in January but then rose to 0.13 per cent in February.
For people in their 30s it rose from 0.17 per cent to 0.32 per cent.
Among those in their 40s it went up from 0.43 per cent to 0.9 per cent, and for 50-somethings it was 1.17 per cent up to 2.1 per cent.
The biggest increase was in the 20s age group, among whom the risk of death rose by 3.15 times, and in people in their 40s, who saw it rise 2.1 times.
The surging death rate came while Brazil was totally over-run by critically ill Covid patients in February and early March.
The Covid death rate among older age groups did not rise to the same extent as it did in younger people, the researchers found
The researchers noted that the death rate increased even when the number of people testing positive was coming down
Brazil has had one of the worst Covid outbreaks in the world, with more than 12million cases and 300,000 deaths (Pictured: People queue for vaccines near Rio de Janeiro in March)
On March 10 the country recorded more than 2,000 deaths in its worst day yet and regional governors warned the country was being buckled by the virus and called for lockdown.
Piaui state chief Wellington Dias described hospitals where infected patients could not even get a bed, let alone the intensive care they required.
‘We have reached the limit across Brazil; rare are the exceptions,’ Dias, who leads the governors’ Covid forum, said earlier this month. ‘The chance of dying without assistance is real.’
More than 80 per cent of intensive care beds were full across 25 major cities in the country at the start of this month, the BBC reported.
Full hospitals are known to have worse survival rates because people can’t get the same level of attention and medical care that they would if there were fewer other patients.
So the increased death rates could have been linked to the fact that hospitals were busier, rather than the new variant.
The country has ranked among those with the worst Covid outbreaks in the world – it has recorded 12.6million cases and 314,000 deaths, second only to the US on both counts.
President Jair Bolsonaro has been constantly dismissive of the virus and allowed it to run rampant, comparing Covid to flu and publicly spreading anti-vaccine myths, hampering the country’s pandemic response.
WHAT DO WE KNOW ABOUT THE BRAZIL VARIANT?
Name: B.1.1.248 or P.1
Date: Discovered in Tokyo, Japan, in four travellers arriving from Manaus, Brazil, on January 2.
Why should we care? The variant has the same spike protein mutation as the highly transmissible versions found in Kent and South Africa – named N501Y – which makes the spike better able to bind to receptors inside the body.
It has a third, less well-studied mutation called K417T, and the ramifications of this are still being researched.
What do the mutations do?
The N501Y mutation makes the spike protein better at binding to receptors in people’s bodies and therefore makes the virus more infectious.
Exactly how much more infectious it is remains to be seen, but scientists estimate the similar-looking variant in the UK is around 56 per cent more transmissible than its predecessor.
Even if the virus doesn’t appear to be more dangerous, its ability to spread faster and cause more infections will inevitably lead to a higher death rate.
Another key mutation in the variant, named E484K, is also on the spike protein and is present in the South African variant.
E484K may be associated with an ability to evade parts of the immune system called antibodies, researchers from the Federal University of Rio de Janeiro said in a scientific paper published online.
However, there are multiple immune cells and substances involved in the destruction of coronavirus when it gets into the body so this may not translate to a difference in how people get infected or recover.
Do our vaccines work against it?
There are concerns that vaccines might be less effective against the Brazilian strain, with trials of the Johnson & Johnson jab finding it was slightly less effective in Latin America at preventing mild or moderate cases.
However, the trials found it still prevented hospitalisations and deaths.
No studies have tested the Oxford/AstraZeneca vaccine against the P1 variant, while Moderna and Pfizer say their mRNA coronavirus vaccines should work against variants with the E484K mutation, with early results showing that these vaccines are only slightly less effective against the P1 variant.