The use of mosquito nets to prevent malaria in childhood means youngsters are more likely to survive into adulthood, new analysis suggests.

The study in Tanzania found that survival of children who habitually slept under nets was more than 40% higher compared with those who did not.

Until now the long-term effect of malaria control in early childhood has been unclear, researchers said.

It had been suggested that preventing the disease early in life could make people more vulnerable later in life due to a lack of immunity, simply delaying life-threatening illness and death.

But researchers suggest estimates from the analysis contradict this theory by finding no evidence that prevention in early life leads to a surge in deaths later on.

Dr Salim Abdulla, principal scientist at Ifakara Health Institute (IHI), Tanzania, and study author, said: “We have known for a long time that bed nets save young lives, but we never knew for sure how long the benefits persisted.

“Our study shows that preventing malaria in early childhood has effects that last into adulthood.”

In 2020 the disease killed more than 600,000 people and is especially dangerous for children.

Common in sub-Saharan Africa, malaria is caused by a parasite transmitted through mosquito bites.

In regions where it is endemic, sleeping under a bed net treated with insecticide is one of the most effective ways to protect young lives.

The study followed more than 6,700 children from 1998, tracking them again in 2019 to find out what happened to them.

Dr Gunther Fink, associate professor of epidemiology and household economics at the University of Basel and the Swiss Tropical and Public Health Institute, and first author, said: “It is reassuring to see these long-term benefits, which further highlight the remarkably high returns to investing into early childhood infectious disease prevention and early life health more generally.”

Dr Joanna Schellenberg, professor of epidemiology and international health at the London School of Hygiene & Tropical Medicine (LSHTM) and last author on the paper, said: “While our study shows the survival benefit of early-life malaria control persists until adulthood, it also reveals the potential of long-term community-based research.”

Co-author Sigilbert Mrema, research scientist with IHI, said: “One of our respondents was overjoyed simply to be told his exact date of birth.

“This type of long-term study is important not only in monitoring health but also in strengthening civil registration.”

The researchers acknowledge limitations of the study, including that there was no information on children who died prior to the first study visit, which means survival rates are not representative of all births.

The study, published in the New England Journal of Medicine, was led by researchers from IHI, LSHTM, and the Swiss TPH.