The new coronavirus variant spreading rapidly in England does not appear to cause more serious illnesses, according to the first paired study of people infected with the new B.1.1.7 strain against those with other variants.
Susan Hopkins, senior medical consultant at Public Health England, who conducted the research, said that “it suggests that the new variant does not cause more serious illness or increased mortality, but we are continuing our investigations to understand this better.”
Scientists have struggled to learn more about the new variant of the coronavirus that devastated the Christmas plans of millions of people in Britain and left the UK largely isolated from the rest of the world, with travel bans imposed by other countries. The new strain was first detected in the United States on Tuesday.
The PHE researchers compared 1,769 people infected with the new variant with 1,769 who had what they called a “wild type” virus. The individuals were matched for age, sex, area of residence and time of testing.
Forty-two people in the group were admitted to the hospital, of which 16 had the new variant and 26 the wild type. Twelve of the variant cases and 10 of the comparators died within four weeks of testing. Neither hospitalization nor differences in mortality were statistically significant.
The researchers also looked for possible reinfections to see if the mutations in B.1.1.7 made it more likely that people would contract the virus a second time. Again, the results were reassuring.
Only two reinfections were detected in the variant group at least 90 days after an initial infection, versus three in the comparator group.
Taking a larger national sample of cases, instead of the corresponding controls, the PHE estimated that the rate of reinfection was 0.6 per 1,000 positive tests, regardless of whether or not people had the new variant.
But PHE researchers confirmed that B.1.1.7 is more contagious than the so-called wild type. In a separate analysis of data from the NHS Test and Trace, the national contact tracking system, they found that 15 percent of people whose contact had the new variant became infected, compared with 10 percent who were in contact with someone who carried a wild-type virus.
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A different study by PHE with the University of Birmingham confirmed previous scientific suggestions that B.1.1.7 leads to higher levels of coronavirus in the upper respiratory tract.
The research, which was published online but has not yet been peer-reviewed, found that 35 percent of patients infected with the new variant had very high levels of coronavirus in the test samples, compared with 10 percent of patients without the variant.
This higher “viral load” is likely to make B.1.1.7 more transmissible to others. Scientists are now eager to find out if it affects the course of the disease in any way, even if it does not appear to affect overall hospitalization or mortality rates.
More than 20 countries worldwide have detected cases of B.1.1.7. Denmark reported 33 – the largest number outside the UK.