Mystery shrouds growth in Covid cases in young people
Messages of support flooded Brazilian social media circles last week after news that 35-year-old actor Thomás Aquino, star of the critically acclaimed 2019 western thriller Bacurau, had gone into intensive care with a severe case of Covid-19.
He suffered a pulmonary embolism but was eventually discharged after spending 10 days in intensive care.
“It is Thomás’ wish for me to inform you,” tweeted Bacurau director Kleber Mendonça Filho, “take care of yourselves, wear a mask, remain isolated whenever possible, ignore this government.”
A recent study from the Brazilian Intensive Medicine Association showed that patients aged under 40 now make up the majority of those hospitalised in the country’s ICUs.
Furthermore, a third of all individuals in Covid-19 intensive care beds in March had no prior health conditions, up from 25 per cent in February.
“What we’re seeing is the oversaturation of the health system,” says Márcio Nehab, a paediatrician and infectious disease expert at the IFF/Fiocruz hospital in Rio de Janeiro.
“The [P1] coronavirus variant has been shown to be more transmissible, and hospitals can’t handle this increased number of cases.”
While there is a concern about mounting case numbers among young adults, Dr Nehab stresses that this has not spread to children and adolescents, who largely suffer from milder cases of Covid-19.
However, there were some fatalities among the young: data from Brazil’s health ministry shows that 1,244 children died from Covid-19 in 2020. And Dr Nehab says those numbers are likely to be underestimated.
“It’s scary, especially when you compare it with the US, where just 279 children died from the coronavirus last year,” he said.
Some 568,000 people have died in the US, compared to 370,000 in Brazil. But it’s not only Brazil which is reporting rising numbers of cases and deaths among young people.
Data show that 48 per cent of Covid-19 positive patients in Mumbai between January and March were below the age of 40, and 65 per cent of newly hospitalised patients in Delhi are under the age of 45, according to the Chief Minister of Delhi, Arvind Kejriwal. In the city of Bengaluru, under 40s made up 58 per cent of infections in early April, compared to 46 per cent at the same time last year, according to figures from Covid19India.org.
“We are seeing relatively younger patients in the ICUs than during the previous surge, roughly double the numbers. And in the general wards we are seeing a third to 40 per cent under the age of 45,” said Dr Sumit Ray, the Medical Superintendent at Holy Family Hospital in New Delhi.
It found that deaths among people aged 20-39 were 2.7 times higher in the second wave than in the first. In the general population they were only 1.15 times higher.
“If [health system] overload was the reason for the increase in the case fatality rate, it would be reasonable to expect that the increase would be similar for different ages and genders,” André Ricardo, epidemiologist at the Leopoldo Mandic School of Medicine in São Paulo, and one of the study’s authors, told the BMJ.
And a study of patients from Parana, a state in the south of Brazil, found that the case fatality rate among 20 to 29 year olds went from 0.04 per cent in January of this year to 0.13 per cent in February, as the variant took hold. Death rates among those in their 30s, 40s and 50s also increased over the same period, the study found.
“These preliminary findings suggest significant increases in CFR in young and middle-aged adults after identification of a novel SARS-CoV-2 strain circulating in Brazil, and this should raise public health alarms, including the need for more aggressive local and regional public health interventions and faster vaccination,” the authors concluded.
Last week there were 5.2 million cases of Covid globally – the largest number reported in a seven-day period – so more cases will also mean more deaths.
Lockdowns have not been implemented in recent months in Brazil and India – whose populations are younger – so young people have been mixing more.
And more transmissible variants will lead to more cases and more deaths. Hospitals that are struggling to cope – India has reported shortages of oxygen and footage has emerged showing patients sharing beds – will also have higher mortality rates.
Ricardo Schnekenberg, a researcher at Oxford University, says reports of younger patients may be due to a “bias” towards treating young, fit people.
“Critical care teams tend to invest more resources and effort into younger, more fit, patients, and these patients are able to survive for longer in ICUs. Thus a natural enrichment of younger patients in ICU wards tends to happen due to bias,” he said.
Danny Altmann, professor of immunology at Imperial College, believes the basic biology of the new variants sweeping through India and Brazil may have a part to play, although he stresses there are no “hard facts” yet.
Levels of the ACE2 enzyme, which enable the SARS-CoV-2 virus to infect cells, change with age. The mutations in the variants also affect how the virus and the enzyme interact, he said.
“Thus, it wouldn’t be too surprising if the mutations were shifting the age distribution of cases,” he says.
But Julian Tang, associate professor of biology at the University of Leicester, believes that the greater numbers of young people affected are simply down to them being out and about.
“Young people transmit more commonly and they do have higher contact frequency, resulting in more cases now than among the elderly – and that may be why we are seeing a higher number, but not necessarily a higher proportion, in hospitals,” he says.