We read with interest the study conducted by Marin-Corral et al.1 and based on the recommendation of reinforcing the annual vaccination campaigns in populations at risk, we wish to make our contribution and emphasize the importance of influenza vaccination in healthcare providers to avoid spreading the infection.

Each year health organizations face seasonal outbreaks of influenza and the corresponding morbimortality associated with these outbreaks. It is estimated that the worldwide incidence of influenza infections is 5.3 cases for every 1000 people and 58,193 people die every year due to this infectious disease.2

In Spain, the seasonal flu epidemic of 2017–20183 generated 5977 confirmed hospitalizations for severe complications of influenza virus infection (HSCIVI) out of which 1281 patients (21.8%) were admitted to intensive care units (ICU); a percentage similar to the one from last season and significantly lower than the one from previous seasons when the influenza A (H1N1) pdm09 virus and influenza A (H3N2) variants were prevalent.

Influenza epidemics are usually managed with vaccination campaigns to prevent cases and complications from happening. Vaccines are officially recommended in our country for certain groups at risk such as the elderly, patients with chronic conditions and institutionalized populations.4

The vaccination of healthcare providers is an effective strategy to reduce influenza-related mortality in hospitalized patients. And yet despite all this, the rates of immunization among healthcare providers are modest. During the influenza vaccination campaign of 2017–2018 in Castile and León the prevalence of immunization among healthcare providers was 30.1% and lower compared to the country's prevalence (31.3%). The highest rate of immunization reported was seen among primary care physicians compared to special care providers and also higher in healthcare providers compared to non-healthcare professionals. The reasons given by several studies5 to explain these rates of immunization are diverse and have to do with organizational barriers associated with the lack of time and accessibility to vaccines, doubts on their effectiveness, fears about side effects, and other personal reasons.

The strategies implemented to increase influenza immunization among healthcare providers are based on informing and training these professionals, although several studies6 claim that establishing mandatory vaccination campaigns is the most effective individual intervention of all followed by a declaration of refusal of vaccines in a vaccine information statement. Other interventions such as greater availability, better awareness of what vaccines represent, and even the implementation of programs with incentives are less effective strategies.

The negative impact due to the low rate of immunization among healthcare providers in the public system and, in particular, in patients hospitalized at ICUs should be approached by legislators, and specialists in occupational safety and health, especially after the confirmation that adequate vaccination strategies have a positive impact on everyone's health.4