Study finds low rate of ‘breakthrough’ COVID-19 infections, fewer symptoms in people vaccinated

London – A study conducted in the UK offers some of the first large-scale and real data on how vaccination protects people from catching a ‘breakthrough’ COVID-19[female[feminine infection, and how well it protects breakthrough patients from becoming seriously ill. The results are encouraging.

The peer-reviewed study published Wednesday in the medical journal The Lancet will help policymakers and epidemiologists close an important gap in understanding the true effectiveness of three of the major vaccines in use around the world.

The US Centers for Disease Control and Prevention, for example, doesn’t have good data on how many people catch COVID-19 after being vaccinated because they decided in the spring to track only severe and symptomatic symptoms. . breakthrough case. The British study, on the other hand, used data from mass testing to determine the number of groundbreaking cases and the degree of illness of these people.

Vaccines were never intended to prevent infections completely, but to reduce the rates of infection in a population and, most importantly, to reduce the severity of the disease in those who get it. The study found that people who contracted the coronavirus when they were fully vaccinated were almost twice as likely to have no symptoms, compared to the general population.

Importantly, the chances of a fully vaccinated person catching COIVD-19 ending up hospitalized with severe symptoms have been reduced by more than two-thirds compared to an unvaccinated coronavirus patient. The survey also found that the risk of breakthrough in patients with long-COVID, with symptoms lasting more than a month, were halved by full vaccination.

It is the latest set of data to offer convincing evidence that vaccines work as intended.

Researchers at King’s College London and Harvard in the United States conducted the study using self-reported data from more than one million people in the United Kingdom who had received Moderna, Pfizer or AstraZeneca COVID-19 vaccines. Research has shown that the risk of serious illness or hospitalization is significantly reduced after a first dose of vaccine, but that protection against serious illness – and contamination from a breakthrough infection to begin with – increases with the full dose.

The data, collected from December 8, 2020 to July 4, 2021, shows that of more than 1.2 million adults who received a first dose, less than 0.5% reported developing breakthrough infections two or more weeks later. have received the vaccine. Of those who received both injections, less than 0.2% experienced a breakthrough infection a week or more after receiving their second injection.

“Among those who experienced a breakthrough infection, the likelihood of this infection being asymptomatic increased by 63% after one dose of the vaccine and by 94% after the second dose,” the study authors wrote in The Lancet.

“We are at a critical point in the pandemic as we see cases increase around the world due to the delta variant. Revolutionary infections are expected and do not diminish the fact that these vaccines do exactly what they were designed to do. designed – save lives and prevent serious illness, “said study co-lead author Dr. Claire Steves of King’s College.” Other research has shown a death rate of up to 27% for inpatients COVID-19. We can drastically reduce this number by keeping people out of the hospital in the first place through vaccination. Our results highlight the crucial role that vaccines play in efforts to prevent COVID-19 infections, which should always include other personal protection measures such as wearing a mask, frequent testing and social distancing. ”

The data also show that the risk of a breakthrough infection is higher for people living in low-income areas, possibly due, the authors say, to closer living quarters and lower overall vaccination rates in the region. these communities. These risks were “more significantly associated with post-vaccination infection after receiving the first dose of vaccine and before receiving a second dose,” according to The Lancet.

As has been found consistently since the coronavirus first appeared, age and underlying conditions, including heart, lung and kidney disease, all seriously increase the risk of severe COVID-19 infection, including included in vaccinated people.

“The increased risks of acute infections for frail older people – especially those who live in nursing homes or need frequent visits to health facilities – and for others living in disadvantaged conditions reflect what we’ve seen the pandemic throughout. These groups are at a greater risk of exposure and are therefore more vulnerable to infection, ”study co-author Dr Rose Penfold, also of King’s College, said in The Lancet. “Health policies designed to prevent infections, including policies regarding the time between the first and second doses and potential booster shots, should prioritize these groups.”

Although the data used for the study did not distinguish between Delta variant infections and other strains of the coronavirus, the vast majority of cases in the UK have been Delta infections since at least early June, and they started to spread rapidly in March. In the United States, Delta became the dominant strain in July and now accounts for almost all new cases.