A new study published in the BMJ has found that the antiviral drug nirmatrelvir may reduce the risk of hospitalization or death in people infected with the SARS-CoV-2 virus and at risk of developing severe COVID-19 disease. The study, which emulated a randomized target trial with electronic health records, included over 250,000 participants with a positive SARS-CoV-2 test result and at least one risk factor for severe illness. Of these participants, 31,524 were treated with nirmatrelvir within five days of testing positive for the virus, while 224,764 received no treatment.
The study found that among people who were not vaccinated, the relative risk of nirmatrelvir in reducing hospitalization or death at 30 days was 0.60, with an absolute risk reduction of 1.83%. In those who received one or two doses of the vaccine, the relative risk and absolute risk reduction were 0.65 and 1.27%, respectively.
For individuals who received a booster dose of vaccine, the relative risk and absolute risk reduction were 0.64 and 1.05%, respectively. In participants with a primary SARS-CoV-2 infection, the relative risk anad absolute risk reduction were 0.61 and 1.36%, respectively, while in those who were reinfected with the virus, the relative risk and absolute risk reduction were 0.74 and 0.79%, respectively.
According to the study, nirmatrelvir was linked with a decrease in the risk of hospitalization or death among participants aged 65 or younger and older, men and women, as well as black and white individuals, and those with varying numbers of risk factors for severe illness. The drug was also effective in those infected during the omicron BA.1 or BA.2 predominant era, as well as the BA.5 predominant era.
This was seen in individuals who were not vaccinated, those who received one or two doses of vaccine, those who received a booster, and those with primary or reinfection. The effectiveness was evident in different age groups, sexes, races, and risk factor categories, as well as in different omicron variant eras. The results were consistent in sensitivity analyses, and controls gave the expected results. This study provides real-world evidence supporting the use of nirmatrelvir in reducing severe covid-19 outcomes.
Nirmatrelvir’s therapeutic value against covid-19 variants of concern was suggested by recent in vitro evidence, but human data were lacking. The effectiveness of nirmatrelvir has been demonstrated in real-world studies conducted in Israel, Hong Kong, and the UK during the omicron era, as well as during eras predominated by BA.1 or BA.2 and BA.5. This study suggests that the antiviral drug is effective regardless of vaccination status, booster dose, or primary/reinfection status.
The study used extensive national healthcare databases from the US Department of Veterans Affairs and emulated target trials. Limitations included potential bias and new variants affecting nirmatrelvir’s effectiveness. Overall, the study suggests that nirmatrelvir may be an effective treatment option for people with SARS-CoV-2 infection who are at risk of developing severe disease.