The two studies, released on Monday by the Lancet Infectious Diseases and the Lancet Public Health journals, look at the highly contagious B.1.1.7 strain which was identified in the UK late last year and has since spread around the world.
The first study was published in the Lancet Infectious Diseases, a monthly journal of original research. It analyzed samples from 341 Covid-19 patients who were admitted to British hospitals in November and December last year and compared their outcomes. Some 58% of the patients were infected with B.1.1.7 and 42% with a different variant. The researchers say they found no evidence of an association between B.1.1.7 and increased risk of severe disease and death in patients. Some 36% of those infected with the British variant developed severe symptoms, compared to 38% of those with the other strain.
The research however confirmed the findings of earlier studies, saying that B.1.1.7 proved more transmissible than other versions of the virus.
The second paper was published in the Lancet Public Health – an online-only, open access title in the Lancet’s family of medical journals. In this case, the researchers investigated symptom reports from nearly 37,000 users of the Covid Symptom Study app in the UK and aimed to confirm or dispel earlier evidence suggesting that “the B.1.1.7 variant increases the risk of admission to hospital and death.”
The authors were referring to a paper published in February by the New and Emerging Respiratory Virus Threats Advisory Group which claimed that it was “likely” that infection with the British strain was “associated with an increased risk of hospitalisation and death” compared to other strains. The paper went on to assure that the “absolute” risk of death per infection remained “low.”
Other studies published in March, such as those in the British Medical Journal (BMJ) and Nature, the weekly international research journal, also suggested that the British strain was more deadly than other Covid-19 variants in circulation.
The research confirmed that the British variant was indeed more transmissible – by 35% – than the previous strains. It failed to find, however, any changes in reported symptoms or the duration of the disease in users diagnosed with B.1.1.7.
The paper goes on to suggest that vaccines were “likely to remain effective against the B.1.1.7 variant” since there was no apparent increase in the reinfection rate.
The researchers stressed however that their findings weren’t the final word on the impact of the British strain.
The B.1.1.7 variant of SARS-CoV-2 which was identified in the UK late last year has since become one of the most dominant strains in the UK, the US and many other countries.