Amid the worst measles outbreak in the United States in a decade, vaccine sceptic Robert F Kennedy Jr, the Trump administration’s Health and Human Services (HHS) Secretary, has affirmed that vaccines protect children.

“Vaccines not only protect individual children from measles, but also contribute to community immunity, protecting those who are unable to be vaccinated due to medical reasons,” Kennedy wrote in an opinion piece published by Fox News on Monday.

He declared that “the decision to vaccinate is a personal one” rather than advising parents to ensure that their children are vaccinated against measles. 

He also asserted that “good nutrition remains a best defense against most chronic and infectious illnesses”.

The Texas Department of State Health Services has confirmed 146 measles cases since late January and one death of an unvaccinated child, the first measles-related death of a US child in over a decade. Seventy nine of the confirmed cases were unvaccinated while the vaccine status of 62 others is unknown.

“Prior to the introduction of the vaccine in the 1960s, virtually every child in the United States contracted measles. For example, in the United States, from 1953 to 1962, on average there were 530,217 confirmed cases and 440 deaths,” wrote Kennedy.

While affirming that HHS would ensure vaccines are “readily accessible for all those who want them”, Kennedy noted that the US Centers for Disease Control and Prevention (CDC) “has recently updated their recommendation supporting administration of vitamin A under the supervision of a physician for those with mild, moderate, and severe infection”.

The CDC noted in a statement last month that “supportive care, including vitamin A administration under the direction of a physician, may be appropriate”.

Vitamin A has been shown to reduce the risk of death from measles by 87% in children younger than two years old, and reduce the length of time the child suffers from diarrhea and fever, according to the Cochrane Review. 

In his first address to HHS staff on 18 February, Kennedy said the he would investigate the childhood vaccine schedule as part of the Make America Healthy Again Commission set up by Trump that Kennedy is chairing.

“Nothing is going to be off limits,” Kennedy said, adding that the commission would investigate the health impacts of pesticides, food additives, microplastics, antidepressants and the electromagnetic waves emitted by cellphones and microwaves.

Last week, the Food and Drug Administration cancelled an advisory committee meeting to discuss the composition of annual flu shots, which then have to be cultured.