RFK Junior is stoking fears about vaccine safety. Here’s why he’s wrong – and the impact it could have

The United States used to be a leader in vaccine research, development and policymaking. Now US Secretary of Health Robert F. Kennedy Jr is undermining the country’s vaccine program at the highest level and supercharging vaccine skepticism.

Two weeks ago, RFK Jr sacked the entire Advisory Committee on Immunization Practices responsible for reviewing the latest scientific evidence on vaccines. RFK Jr alleged conflicts of interest and hand-picked a replacement panel.

On Wednesday, RFK Jr announced the US would stop funding the global vaccine alliance, Gavi, because he claimed that “when the science was inconvenient today, Gavi ignored the science”. RFK Jr questioned the safety of COVID vaccines for pregnant women, as well as the diphtheria, tetanus and pertussis vaccine.

On Thursday, when the new Advisory Committee on Immunization Practices met, the person who first drew RFK Jr into vaccine scepticism, Lyn Redwood, shared disproved claims about a chemical called thimerosal in flu vaccines being harmful.

The undermining of regulation, advisory processes and funding changes will have global impacts, as debunked claims are given new levels of apparent legitimacy. Some of these impacts will be slow and insidious.

So what should we make of these latest claims and funding cuts?

Thiomersal is a distraction

Thiomersal (thimerosal in the the US) is a safe and effective preservative that prevents bacterial and fungal contamination of the vaccine contained in a multi-dose vial. It’s a salt that contains a tiny amount of mercury in a safe form.

Thiomersal is no longer used as a preservative in any vaccines routinely given in Australia. But it’s still used in the Q fever vaccine.

Other countries use multi-dose vials with thiomersal when single-dose vials are too expensive.

In the US, just 4% of adult influenza vaccines contain thiomersal. So focusing on removing vaccines containing thimerosal is a distraction for the committee.

COVID vaccines in pregnancy prevent severe illness

On Wednesday, RFK criticised Gavi’s encouragement of pregnant women to receive COVID-19 vaccines.

A COVID-19 infection before and during pregnancy can increase the risk of miscarriage two- to four-fold, even if it’s only a mild infection.

Conversely, there is good evidence vaccination during pregnancy is safe and can reduce the chance of hospitalisation of pregnant people and of infants by passing antibodies through the placenta.

In Australia, pregnant people who have never received a primary COVID-19 vaccine are recommended to have one. However, they are not generally recommended to have booster unless they have underlying risk conditions or prefer to have one. This is due to population immunity.

COVID-19 vaccine advice should adapt to changes in disease risk and vaccine benefit. It doesn’t mean previous decisions were wrong, nor that vaccine boosters are unsafe.

RFK’s criticism of COVID-19 vaccines in pregnancy may influence choices individuals make in other countries, even when unvaccinated pregnant women are encouraged to consider vaccination.

The diphtheria, tetanus and pertussis vaccine is safe

RFK Jr also questioned the safety of the combined diphtheria, tetanus and pertussis (DTP) vaccine as he announced the withdrawal of US funding support for Gavi.

In the early 2000s, three community-based observational studies reported a possible association between increased chance of death in infants and use of the DTP vaccine.

A few subsequent studies also reported associations, with higher risk in girls, prompting a World Health Organization (WHO) review of safety.

Real world studies are complicated and the data can be difficult to interpret correctly. Often, the very factors that influence whether someone gets vaccinated can also be associated with other health risks.

When the WHO committee reviewed all the studies on DTP safety in 2014, it did not indicate serious adverse events. It concluded there was substantial evidence against these claims.

What will de-funding Gavi mean for vaccination rates?

Gavi, the vaccine alliance, supports vaccine purchasing in low-income countries.

The US has historically accounted for 13% of all donor funds.

However, RFK Jr said Gavi needed to re-earn the public trust and “consider the best science available” before the US would contribute funding again.

Gavi predicted in March that the impact of US funding cuts could result in one million deaths through missed vaccines.

Could something like this happen in Australia?

Australia is fortunate to be buffered from these impacts.

Our vaccine advisory body, the Australian Technical Advisory Group on Immunisation, has people with deep expertise in vaccination. We have robust decision processes that weigh evidence critically and make careful recommendations to government.

Our governments remain committed to vaccination. The federal government released the National Immunisation Strategy in mid-June with a comprehensive plan to continue to strengthen our program.

The federal government also announced A$386 million to support the work of Gavi from 2026 to 2030.

All of this keeps our vaccine policies strong, preventing disease and increasing life expectancy here and overseas.

But to mitigate the possible influence of the US in Australia, our governments, health professionals and the public need to be ready to rapidly tackle the misinformation, distortions and half-truths RFK Jr cleverly packages – with quality information.