The influenza vaccine would reduce the severity of influenza in vaccinated patients who have not prevented the contagion

When influenza vaccination is ineffective in preventing influenza, it could still have an additional effect by decreasing the severity of the disease, according to an epidemiological study in which members of the Research Group on Epidemiology, Prevention and Control of Communicable Diseases - led by the professor Àngela Domínguez, of the Department of Medicine of the UB- and of the CIBER of Epidemiology and Public Health (CIBERESP), of the Carlos III Health Institute. In the work, published in the scientific journal Eurosurveillance, researchers from the Public Health Agency of Catalonia, the Biomedical Research Institute of Lleida and the Public Health Agency of Barcelona have also participated.

The results show that, among those who required admission to the ICU or died, vaccination was less frequent (21.2% of cases) than in the rest of patients with more benign symptoms, of whom 29.7% had been vaccinated. %. In this way, the effectiveness of influenza vaccination to prevent admission to the ICU or the death of all those hospitalized with influenza was 23% and 44% in those over 65. "To these percentages we should add the effectiveness of the vaccine to prevent the flu. These data reinforce the need for influenza vaccination each season for all those who are more likely to have severe forms of influenza, such as people 65 years of age or older, and people with other underlying diseases, in whom influenza vaccination is often it is not enough to prevent infection, "the authors say.

In the study, the researchers point out that a possible explanation of the results would be the role played by the immune system. "Persons previously infected with the virus or who received influenza vaccines could benefit, at least in part, from the preexisting cross-memory of cytotoxic T lymphocytes, which would reduce the severity of the infection, even in the absence of protective antibodies," they conclude. .


Article reference:
Godoy, Pere; Romero, Arantxa; Soldevila, Núria; Torner, Nuria; Jané, Mireia; Martínez, Ana; Caylà, Joan A.; Rius, Cristina; Domínguez, Angela; The Working Group on Surveillance of Severe Influenza Hospitalized Cases in Catalonia. «Influenza vaccine effectiveness in reducing severe outcomes over six influenza seasons, a case-case analysis, Spain, 2010/11 to 2015/16». Eurosurveillance, octubre de 2018. Doi: https://doi.org/10.2807/1560-7917.ES.2018.23.43.1700732