The study tested the effectiveness of childhood vaccination against influenza and the risk of hospitalization due to influenza complications.
"Children vaccinated according to government guidelines are much better protected from influenza than those who only receive one vaccine, said study lead author Hannah Segaloff from the University of Michigan in the US.
According to the researchers, over half of our study population had underlying conditions that may put them at high risk for severe influenza-related complications, so preventing influenza in this group is critically important.
"Our results also showed that the vaccine was effective in three different seasons with different circulating viruses, reinforcing the importance of getting an influenza vaccine every year no matter what virus is circulating," Hannah said.
The retrospective study used data from Clalit Health Services, the largest health fund in Israel, to review the vaccination data of 3,746 hospitalizations of children six months to 8 years old at six hospitals in Israel.
They were tested for influenza over three winter seasons 2015-16, 2016-17 and 2017-18.
Not only do the findings reveal that the flu vaccine reduced hospitalizations associated with the flu by 54 percent, but they show that giving two vaccine doses to children up to age eight who have never been vaccinated or only received one dose previously is more effective than administering one dose, in accordance with the Israel Ministry of Health recommendations.
"Young children are at high risk of hospitalization due to influenza complications. Children with underlying illnesses such as asthma and heart disease have an even greater risk of getting complications. It is important to prevent influenza infections in these populations," said study co-author Mark Katz from The Clalit Research Institute in Israel.
The findings support health organizations' recommendations to vaccinate children against influenza every year, preferably before the onset of winter or early childhood.
Children under five are defined as having a high risk of influenza complications, the researchers said.