Researchers studying how the disease progresses in the body, and what factors help recovery, said the key to reducing the risk of death could lie in stimulating the immune response in the early stages of the infection.

“The severity of covid-19 infection in children is less than in adults. The differentiator could be a fully functional thymus gland in children, which can help mount a robust adaptive immune response when the virus attacks the body,” said Dr U.S. Vishal Rao, member, consultative group, to the principal scientific adviser, government of India.

The thymus gland is located between the lungs, and produces T-cells, the white blood cells that fight infections. Fully formed in childhood, it starts shrinking in adolescence.

“Those patients with a stronger thymus gland recovered,” explained Dr Rao, who led a study on this.

The findings are being reviewed by medical journal Lancet.

“The more this gland regresses with ageing, the more susceptible one is to the virus. Even young people with low immunity were susceptible,” said Dr Rao.

“Our research of pre-treatment of cells with small amounts of interferons (signalling proteins released by the body when it detects a virus) can enhance the response to viral infection significantly. SARS-CoV-2 impairs the production and function of these cytokines,” he said.

Interferons are part of the larger category of cytokines, which send signals to cells telling them to respond to a virus.

“There is a high possibility that the presence of cytokines was adequate to fight the virus in those who recovered,” said Dr Gururaj Rao, a molecular and cell biologist.

“If it is a weak thymus gland that is killing people, then it is time we strengthened the all-important organ by eating vitamin-C-rich foods such as dark leafy greens, tomatoes, sprouts, broccoli, as well as almonds,” said a veteran family physician.