British officials say people who get the contagious variant of the coronavirus may be at higher risk for death. That’s why it might be.

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A row of ambulances parked outside Royal London Hospital. Daniel Leaf-Olivas / AFP via Getty Images

British Prime Minister Boris Johnson announced last week that people infected with the coronavirus variant first reported in the country may be at a higher risk of death than those who get the original virus.

“There is evidence that the new variant could be associated with a higher mortality rate,” he told a news conference on Friday.

Studies have shown that the variant, known as B.1.1.7, is more contagious than its viral predecessors. But evidence so far has not suggested that the tension was more deadly.

“While an average of 10 out of a 1,000 older people in the UK have died from the old variant, the new variant appears to be increasing to 13 out of 1,000 people,” Patrick Vallance, the British chief scientist, said on Friday. However, he emphasized that the evidence was “uncertain”.

Some experts have since pointed out that just because more people infected with this variant die does not mean it is more deadly than other versions. It could be that the UK healthcare system is overloaded by the country’s coronavirus effects, or that the increase in the transmission of the strain enables it to infect more people with underlying health conditions.

30% higher mortality rate, with reservation

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British Prime Minister Boris Johnson. Toby Melville – WPA Pool / Getty Images

Johnson’s announcement was based on research collected by the UK’s New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG), which examined the differences in deaths between people in the UK infected with B.1.1.7 and those with other strains, analyze.

After examining variables such as the age, gender, and geographical location of a patient, researchers from the London School of Hygiene & Tropical Medicine and the Imperial College London found that, on average, people infected with B.1.1.7 Had 30% higher deaths. course.

A follow-up analysis by Public Health England analyzed the data collected between 23 November and 4 January and found that B.1.1.7 was 65% more lethal than other strains. Researchers at the University of Exeter, meanwhile, looked at samples collected since October 1 and found that people infected with the variant would die almost twice as often.

However, the researchers found no evidence that people infected with B.1.1.7 were hospitalized at higher rates.

“If there is an increase in the severity of infection,” NERVTAG wrote, “we would also expect to see an increase in the risk of hospitalization.”

However, William Schaffner, an expert on infectious diseases at Vanderbilt University, told Insider that it is possible that fewer people go to hospitals for treatment, especially given reports that British hospitals are on the verge of being overwhelmed.

‘Deaths will get out of control if your health system comes under pressure’

The World Health Organization said on Friday that the data used by British officials had yet to be seen before confirming whether the B.1.1.7 variant did cause serious illness.

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A COVID-19 patient is loaded into an ambulance in London, England. Getty

If the stress is indeed more lethal, one possible reason could be that people infected with B.1.1.7 have higher virus load, which means they produce more viral particles when infected. Higher viral loads, according to multiple studies, are associated with a higher risk of death and worse disease.

“That was the first thing that definitely came to my mind,” Schaffner said. “It will make very good sense.”

It can also explain the increased contagion, because the more viral particles a person spits, the greater the chance that they will infect others.

But it is also possible that the increased transferability of the variant indirectly causes a higher mortality rate, although the stress itself is not more lethal. B.1.1.7. has several mutations in the code for its vein protein, which the virus uses to invade cells, making it between 50-70% more contagious than the original.

One such possibility is that because there are so many more cases in the UK, healthcare systems are stressed and resources scarce. This in itself can lead to higher mortality rates.

“If your affairs get out of control, your deaths will get out of control as your health system comes under pressure,” Mike Ryan, executive director of the WHO’s health emergency program, said at a news conference on Friday.

It is also possible that the increased transmission of the strain ensures that the virus infects more people with a higher risk of serious diseases.

“It can not be because the virus itself makes the individual more likely to get severe COVID,” Schaffner said. “It could simply be a matter of a more contagious virus that is vulnerable to people who are older or have underlying health problems such as diabetes or lung disease.”

A more transferable voltage can lead to a higher death rate than a more lethal

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An overcrowded London street as seen on 18 October 2020. Matthew Chattle / Barcroft Media via Getty Images

The British researchers’ conclusions were based on just 8% of the total deaths that occurred in the UK during the study period, and therefore Vallance still considers the evidence to be ‘not yet strong’.

“The results of all studies may therefore not be representative of the total population,” NERVTAG concluded.

To determine which strain infected and killed a person, scientists must genetically sequence a sample of the patient’s blood or saliva. The process is time consuming and samples collected from patients are not always sent for sequencing.

The data also did not take into account any underlying health conditions in people who died from COVID-19, which could also have skewed the mortality rates.

Regardless of the quality of the data, and regardless of whether the new strain is actually more lethal or not, its spread will almost certainly lead to a higher death toll, as infected individuals will spread it to more people.

Adam Kucharski, an epidemiologist at the London School of Hygiene and Tropical Medicine, compared three hypothetical scenarios on Twitter to demonstrate it.

Suppose the original strain of the coronavirus has a reproductive value (meaning the average number of people infecting one sick person) of 1.1 and kills 0.8 people out of every 100 who become ill. In a population of 10,000 people, the virus would kill 129 people within a month.

But say now two new tribes have emerged, one of which is 50% more deadly, while the other 50% is more transmissible. The stress, which is 50% more deadly, would kill about 193 of the 10,000 people in a month. But the stress, which is 50% more transmissible, would result in 978 of the 10,000 people dying in that time due to its rapid spread.

Anna Medaris-Miller contributed reporting to this story.