Vaccines effective at reducing severe illness: Lancet study
People infected with the SARS-CoV-2 virus after receiving one or two COVID-19 vaccine doses have significantly lower chance of severe disease or hospitalisation than unvaccinated individuals, according to a large-scale study published in The Lancet Infectious Diseases journal on Tuesday. Researchers also found that the odds of experiencing long COVID — illness lasting 28 days or more after a positive test — were reduced to half for people who received two vaccines doses.
People most vulnerable to a breakthrough infection after their first vaccine dose included frail older adults, 60 years and older, and those living with underlying conditions such as obesity, heart disease, kidney disease, and lung disease, they said. The study found that in all age groups, people living in deprived areas, such as densely populated urban settings, were more likely to experience a breakthrough infection.
These factors were most significantly associated with a post-immunisation infection after receiving the first vaccine dose and before receiving a second dose, it found. “We are at a critical point in the pandemic as we see cases rising worldwide due to the Delta variant. Breakthrough infections are expected and don’t diminish the fact that these vaccines are doing exactly what they were designed to do — save lives and prevent serious illness,” said study co-lead author Claire Steves of King’s College London, UK.
“Other research has shown a mortality rate as high as 27 per cent for hospitalised COVID-19 patients. We can greatly reduce that number by keeping people out of the hospital in the first place through vaccination,” Steves said. The study highlights the crucial role vaccines play in larger efforts to prevent COVID-19 infections, which should still include other personal protective measures such as mask-wearing, frequent testing, and social distancing.