Professor Michael Edelstein: Measles outbreak and the trust gap in vaccines

A new study by researchers at Bar-Ilan University has found a measurable global decline in parental trust in childhood vaccines following the Covid pandemic, a shift that public health experts warn could contribute to renewed outbreaks of preventable diseases.

The research, conducted in Israel and the UK, examined vaccination behavior among parents with multiple children, at least one born before the pandemic and one after. According to the findings, approximately 5% of parents who vaccinated their children prior to Covid chose not to vaccinate children born after the pandemic.

Professor Michael Edelstein, a public health specialist involved in the study, said the figure may appear modest but carries serious implications. For highly contagious diseases such as measles, even small drops in vaccination coverage can be enough to trigger outbreaks.

“5 percent is more than enough to cause problems with infectious diseases,” Edelstein said. “This is particularly true for measles, which is one of the most contagious viruses we know.”

The study found nearly identical trends in Israel and the UK, suggesting the decline in trust is not country-specific but part of a broader global pattern linked to the pandemic.

Researchers sought to understand not only changes in behavior but also the reasons behind them. The leading concern cited by parents was vaccine safety, followed by a broader loss of trust in healthcare systems. Concerns about whether vaccines work were less common.

Edelstein said the Covid pandemic created confusion that continues to affect public attitudes toward routine immunizations.

“There were vaccines developed very quickly, changing guidelines, and different advice in different countries,” he explained. “That undermined trust, even though routine childhood vaccines are completely different. These are vaccines that have been used safely for decades.”

The measles vaccine, for example, has been in use since the late 1960s, with the current combined measles, mumps, and rubella vaccine introduced in the late 1980s. Two doses provide more than 99% protection and offer long-term immunity.

Despite this, Israel has seen a resurgence of measles cases in recent months. According to health officials, the disease, which was once close to elimination, has returned in areas with lower vaccination coverage.

Measles spreads through airborne transmission and can infect people after only brief exposure. While most patients recover, a significant minority develop severe complications, including hospitalization and death. Children and individuals with compromised immune systems are particularly vulnerable.

Edelstein said that during the pandemic, health authorities often failed to communicate uncertainty clearly, which may have contributed to public distrust.

“In a crisis where data is limited and evolving, transparency is critical,” he said. “When advice is presented with certainty and later changes, people feel misled.”

The study also examined the role of social media in shaping vaccine perceptions. While most parents reported relying primarily on healthcare professionals and official health websites for information, a substantial minority said social media influenced their views.

“Misinformation spreads very quickly,” Edelstein said. “It is often easier to share a dramatic story than to explain scientific evidence.”

Beyond hesitancy, the research highlighted practical barriers to vaccination, including difficulty securing appointments and limited access to clinics. Edelstein noted that improving convenience can be as important as addressing concerns.

“In many cases, people are not opposed to vaccination but are busy or face logistical challenges,” he said.

The study also identified examples of successful vaccine uptake, including within Israel’s Arab population, which has some of the highest vaccination rates in the country despite socioeconomic challenges. Researchers attributed this to culturally accessible healthcare, language-appropriate communication, and strong community norms around vaccination.

Edelstein emphasized that rebuilding trust will take time and sustained engagement.

“Trust is slow to build and easy to lose,” he said. “But it can be rebuilt through transparency, accessibility, and respectful dialogue.”

As health officials work to contain current outbreaks, researchers warn that without renewed confidence in vaccination programs, additional preventable diseases could reemerge.