US flu vaccine approved, but CDC guidance stalls after policy upheaval

A newly approved flu vaccine for older adults in the US has become the latest example of how federal vaccine guidance has stalled amid upheaval in the country’s public health system. While the Food and Drug Administration approved mFlusiva after it tested well, the Centers for Disease Control and Prevention has not issued any recommendation on how doctors or the public should use it.

The pause reflects a wider breakdown in the long-running process through which the CDC reviewed evidence and issued vaccine advice. That process was disrupted after Health Secretary Robert F Kennedy Jr overhauled the advisory system, and the changes were then challenged in court. As a result, guidance on new vaccines has slowed, while debates on other vaccine questions have lost a formal public forum.

For 60 years, the Advisory Committee on Immunization Practices, or ACIP, guided the CDC’s vaccine recommendations through public meetings, data reviews and input from health groups. Its votes were usually adopted by the CDC director and became the government’s guidance, which in turn helped determine whether public and private insurers would pay for shots. Kennedy, appointed by President Donald Trump to oversee federal health agencies including the CDC, dismissed the committee last year and replaced it with a group that included several anti-vaccine voices. Medical groups, including the American Academy of Pediatrics, sued, and in March a federal judge said Kennedy had likely violated federal procedures, halted the new panel’s meetings and suspended his decision to cut the number of vaccines recommended for children.

Many in medicine and public health welcomed the ruling. Dr Jason Goldman, president of the American College of Physicians, said he hoped “it will mean a return to a transparent and evidence-driven process that safeguards the health of all communities and the best interests of our patients.” But the court order did not restore the old system. Instead, doctors’ groups that once worked with ACIP began making their own assessments with a University of Minnesota researcher, though not in public, and issued separate recommendations. Private health insurers decided to follow those recommendations and continued to pay for shots backed by those organisations.

Some of those recommendations have updated earlier federal advice. ACIP had recommended that a vaccine against respiratory syncytial virus, or RSV, be given to women late in pregnancy between September and January in most of the US, when RSV infections are usually most common. But as RSV season can stay active for longer, medical groups recently said the shot should be offered through the beginning of March. “We all recognized this needs to evolve,” Chris Regal, director of clinical innovation at America’s Health Insurance Plans, said in a recent webinar. The official CDC guidance, however, has not changed.

The uncertainty is also visible in flu and COVID-19 policy. MFlusiva is the first flu vaccine made with mRNA technology, which was central to the response to the COVID-19 pandemic. Kennedy has criticised mRNA vaccines and last year cancelled contracts for developing new ones. The vaccine was eventually fully approved by the FDA for people aged 50 to 64, but the CDC said this month that it was keeping last year’s flu vaccine endorsements because of “legal uncertainties and inquiries”, leaving mFlusiva off the list of flu shots recommended to the public this autumn. Medical societies, however, are recommending it as an option. In another case, although updated COVID-19 vaccines were approved by the FDA, the government took until this week to confirm that orders for those shots could be placed through Vaccines for Children, a programme that covers children without health insurance.

Questions are also piling up over the HPV vaccine, which is given to preteens to help prevent certain cancers. Two doses are currently recommended, but some recent research has suggested one shot may be enough, at least for girls. ACIP had formed a working group in 2024 to review that evidence, but the effort stopped when Kennedy dismissed the committee. In January, he moved on his own to reduce the recommended number of doses to one as part of a broader cut to the childhood vaccination schedule, but that decision was suspended by the judge. Experts are still studying the timing and duration of protection from a single dose, especially in boys, and the American Academy of Pediatrics is considering whether to change its advice later this year.

Jason Schwartz, a Yale University health policy researcher who studies government health agencies, said the disruption has left no clear route for turning evidence into formal policy. “We find ourselves at a point where even if credible evidence (for a new vaccine policy) has reached a tipping point, we don’t have an obvious mechanism that can formalize that change,” he said. He added, “The credibility of the Trump administration, when it comes to vaccine recommendations, is so compromised in the eyes of the mainstream medical and public health communities, that even recommendations that might align with where the public health community was trending are likely to be viewed with scepticism or distrust.” At the same time, the administration is considering changes to the federal categories for vaccine recommendations, though no detailed proposal has been released. An alliance of 15 Democratic state governors said the move could add to confusion. “It’s Governors and their residents who bear the brunt of any increased disease outbreaks due to confusion related to hastily made federal changes,” Angela Botticella, managing director of the Governors Public Health Alliance, said in a statement.

In sum, the row over vaccine policy in the US has left federal guidance delayed or unclear on issues ranging from the new mRNA-based flu shot to COVID-19 coverage and HPV dosing, even as medical groups and insurers try to fill the gap with their own decisions.