The US has announced three deaths associated with measles last week, among them a seven-month-old baby in New York and a postpartum woman in Pennsylvania, underscoring the need for a more aggressive vaccination approach – but US recommendations haven’t changed.

Dismantling the Advisory Committee on Immunization Practices (ACIP) made it harder for the US to respond to the measles outbreak, with vaccine recommendations staying the same during a historic rise in cases and deaths, four former advisers say.

A functioning committee would likely be considering recommendations on reaching adults with vaccines; moving up the childhood schedule for measles, mumps, and rubella (MMR) vaccination in stricken areas; and pinpointing exactly which groups and areas need vaccination campaigns, they said.

Months after Robert F Kennedy Jr, the secretary of the US Department of Health and Human Services (HHS), replaced vaccine advisers with his own handpicked allies, a federal judge halted the committee’s work, finding that the Trump administration had failed to constitute the committee properly.

The ACIP makes recommendations to the US Centers for Disease Control and Prevention (CDC) on vaccine policy – and it “definitely” would discuss updating its advice as measles continues to spread, said Yvonne “Bonnie” Maldonado, chief of infectious diseases in the department of pediatrics at Stanford Medicine and a former member of the ACIP.

Now, “we don’t have an ACIP”, Maldonado added. “That’s going to impact disease and deaths in the US.”

The committee was monitoring the measles outbreak early last year before Kennedy disbanded it, and his replacements did not publicly evaluate evidence on the outbreak. The CDC is now taking nominations for a new committee, but the appointment process can take months or years – and the process for making or changing recommendations is also lengthy.

“It typically took between 12 to 18 months from the start of considering new recommendations to adopting them,” said Noel Brewer, a distinguished professor of health behavior at the UNC Gillings School of Global Public Health and a former ACIP member. In the meantime, the outbreak continues accelerating.

The seven-month-old baby who died in New York state wasn’t vaccinated against measles, officials said on Monday. Another infant died in the measles outbreak in Wisconsin, officials announced on Thursday. Both states marked their first measles-associated deaths in three decades.

In normal times, babies in the US don’t receive their first MMR shots until they turn one. But during outbreaks, babies at risk of infection can get the shot as early as six months of age – one of a handful of recommendations from the CDC that is receiving less attention than it normally would, experts say.

The advice on vaccination during outbreaks could be highlighted more, and recommendations could be changed to “tell the pediatricians and providers we are in a huge outbreak”, said Edwin Asturias, professor of pediatric infectious disease at the University of Colorado and a former ACIP member.

The CDC also offers the option of moving up the MMR second shot in order to make sure children in outbreak areas are fully protected against the virus. During an outbreak, it can be given as soon as four weeks after the first dose. The shot is usually given between the ages of four and six.

The delay between doses could be contributing to what Asturias calls a “group of susceptibles” who were not protected from measles for decades and are now falling ill and dying.

Some people are ideologically opposed to vaccines, while others don’t have steady access to healthcare. “But that’s only part of the explanation,” Asturias said. The number of visits to doctors decreases dramatically after the second year of life, with fewer opportunities to get the shots. “By delaying the second dose of immunization to four to six years, are you more likely to miss or not to give a second dose to many children?” he asked.

A properly appointed ACIP would look at such data points to “try to understand how this immunization or protection gap came about”, Asturias said.

In the US, vaccine mandates for children are set at the state and local level, tied to daycare and school attendance. But moving the recommendation earlier might increase vaccination rates, since families tend to have higher levels of trust in their doctors than in local officials, for example.

An unusually high number of adolescents and young adults are now getting sick and dying from measles. The vaccine advisers would likely explore why, and what could be done to reach them.

“Are you really monitoring how many adults are getting infected? I doubt it,” said Paul Offit, an infectious diseases physician at the Children’s Hospital of Philadelphia and a member of the ACIP two decades ago. “Are we trying to vaccinate them? It’s harder. You can have school mandates, but what do you do for adults?”

It is especially important to reach unvaccinated or under-vaccinated people before they become pregnant, because the vaccines cannot be given during pregnancy. Congenital measles cases – when a baby gets sick in utero – have risen sharply this year, officials in Pennsylvania warned recently.

Such infections threaten the lives of newborns and pregnant people alike. A 21-year-old woman in Pennsylvania died soon after childbirth from measles complications, officials announced this week. Earlier this year, a measles-infected baby died soon after birth.

“That’s the actual heart of the situation,” Maldonado said. “What we’re seeing now is something I literally have never seen myself, and I’m a seasoned infectious disease clinician,” she added. “To have even one case used to be a remarkable occurrence, but now they’re having so many.”

Anyone beginning cancer therapy or other immune-suppressing treatments should also make sure they’re protected by vaccines first, Asturias said. And anyone who was born between 1968 and 1989 may have only received one shot, and should get a second dose.

The ACIP should also work to identify which groups of people and regions are most at risk and how to reach them, said Brewer.

“Measles vaccination rates are pretty high in most places, but there are places where it’s very low, and the United States does not have a good mechanism for identifying these geographical areas and responding in them,” Brewer said.

The ACIP and the CDC offer recommendations based on evidence that is sometimes not publicly available. But states can take action on their own to change vaccination recommendations. “The decisions are up to the states and the counties,” Maldonado said.

With measles, “there are serious risks” and “most of the bad stuff happens to young babies under a year of age”, Maldonado said. Hospitalizations, complications and deaths are more common in this group – and the risks persist long after the rash fades. Maldonado has cared for two children who developed subacute sclerosing panencephalitis years after contracting measles.

“They’re terrifying cases,” she said.

Yet US officials have lagged in public communications about the risks – and how preventable they are, Maldonado said. Erica Schwartz, the CDC’s director, drew criticism for her silence on the outbreaks and the importance of vaccination.

“She came into CDC in the middle of a huge set of outbreaks and didn’t talk about it for weeks,” Maldonado said. For families seeking guidance, “it’s already pretty chaotic right now, and it’s unfortunate – nobody knows where to turn”, Maldonado said.

US officials need to speak with “one voice” to outline a plan for addressing the outbreak, Brewer said. “The US has a terrible measles problem right now, one that is largely avoidable. We need to get vaccination rates up.”

He added: “That’s really the key priority: just get the shot.”