Our herd immunity has been compromised
In Indonesia, the ancient threat of measles has found new life not in the absence of medicine, but in the presence of doubt — doubt seeded by social media, nurtured by fear, and in some cases rooted in sincere religious conviction. With over 63,000 cases recorded in 2025 and the country ranking second in the world for measles burden, the crisis reveals how swiftly misinformation can erode the collective immunity that took generations to build. The government races to close the gap through emergency campaigns and interfaith outreach, but the distance between the 75% vaccination rate achieved and the 95% threshold required for herd immunity is measured not just in numbers, but in the stories of parents who believe, with genuine care for their children, that they are making the safer choice.
- Indonesia recorded more than 63,000 measles cases in 2025 and over 8,000 suspected cases in just the first three months of 2026, placing it second only to war-torn Yemen in global measles burden.
- Anti-vaccine influencers are outpacing public health messaging on nearly every major social media platform, selling herbal remedies and spreading false claims — including the dangerous myth that natural infection offers better protection than vaccination.
- Religious hesitancy compounds the crisis: some Muslim parents refuse vaccines containing porcine-derived ingredients, even though Indonesia's highest Islamic authority issued a fatwa in 2018 declaring such vaccines permissible for public health.
- The government launched emergency vaccination campaigns across roughly 100 regions in March, partnering with religious organizations and deploying boosters for over 220,000 health workers in an effort to reverse the slide.
- Despite official optimism about reduced transmission, only 75% of children are receiving both required doses — far short of the 95% threshold needed for herd immunity, and the national goal of measles eradication by year's end is now widely considered out of reach.
Fitri Fransiskha, a forty-year-old mother of four in Banten, has not vaccinated any of her children against measles. Her hesitation began when her firstborn ran a fever after an infant vaccination — a single event that, amplified by a relentless stream of social media posts warning of paralysis and behavioral disorders, hardened into firm conviction. She relies instead on nutritious food and vitamins, trusting what she can see and control. Across Indonesia, many parents are making the same calculation, withdrawing from inoculation at precisely the moment the country faces a public health emergency.
Indonesia recorded more than 63,000 measles cases in 2025, resulting in 69 deaths. In the first three months of 2026 alone, authorities logged over 8,000 suspected cases and 10 more deaths. The country now trails only Yemen — a nation shattered by war — in its measles burden. Research by Indonesian data firm Drone Emprit found anti-vaccine rhetoric saturating nearly every major social media platform, with a telling asymmetry: though fewer in number, anti-vaccine voices are louder and more persistent than pro-vaccine ones. Many influencers have turned their platforms into storefronts for unproven herbal remedies, and in March, AFP fact-checkers were forced to debunk the viral claim that natural measles infection provides superior protection to any vaccine.
For some parents, the hesitation is rooted not in distrust of science but in faith. Indonesia is a Muslim-majority nation, and certain vaccines contain porcine-derived components — a concern for parents observing Islamic dietary law. Yusran, a forty-six-year-old entrepreneur in Makassar, has not vaccinated any of his five children on these grounds, even as he gives thanks for their continued health. The Indonesian Ulema Council addressed this directly in 2018, issuing a fatwa declaring vaccines permissible for the sake of public health even when they contain porcine gelatine — but the ruling has not reached every household.
The government has responded with urgency. In March, it launched emergency vaccination campaigns across roughly one hundred regencies and cities, partnered with religious organizations, and administered boosters to more than 220,000 health workers. Officials report that measles transmission has dropped. Yet the underlying numbers remain troubling: the share of infants receiving a first vaccine dose fell by ten percentage points last year compared to 2024, and currently only about three-quarters of children receive both required doses. The threshold for herd immunity stands at 95%. Epidemiologist Riris Andono Ahmad of Gadjah Mada University stated it without ambiguity: "Our herd immunity has been compromised." The government's goal of measles eradication by the end of 2026 now appears beyond reach — leaving a vaccination campaign to race against a virus that requires only the smallest gap in immunity to find its next host.
Fitri Fransiskha is a forty-year-old mother of four living in Banten, on Java's western edge. She has not vaccinated any of her children against measles, even as the virus tears through Indonesia at a pace that has made her country the second-most afflicted in the world. Her hesitation began years ago, when her firstborn ran a fever after receiving a tuberculosis vaccination as an infant. That single event, amplified by a steady stream of social media posts claiming vaccines cause paralysis, behavioral disorders, and worse, hardened into conviction. "Posts like that worried me," she said in a recent phone interview, "and it made me think my decision not to vaccinate my children was probably the right one." Instead, she relies on what she can control: nutritious food and vitamins.
Fitri is not alone. Across Indonesia, a growing number of parents are making the same calculation, turning away from inoculation at precisely the moment the country is confronting a public health emergency. Last year, measles cases exceeded 63,000, resulting in 69 deaths. In the first three months of 2026 alone, authorities recorded more than 8,000 suspected cases and 10 additional deaths. The disease, which once seemed nearly vanquished globally, has returned as a significant threat. Indonesia now trails only Yemen—a nation ravaged by war—in measles burden.
The crisis is being fueled by misinformation that moves faster than any government response. A study by Indonesian data firm Drone Emprit found anti-vaccine rhetoric present on nearly every major social media platform in the country, reaching audiences of substantial size. The firm's founder, Ismail Fahmi, noted a peculiar asymmetry: anti-vaccine voices, though numerically smaller, tend to be louder and more persistent than their pro-vaccine counterparts. Many influencers have weaponized their platforms to sell unproven herbal remedies as alternatives to vaccination. In March, AFP's fact-checking team debunked a particularly pernicious claim circulating online—that contracting measles naturally provides better protection than any vaccine.
For some parents, the hesitation runs deeper than distrust of government or fear of side effects. Indonesia is a Muslim-majority nation, and certain vaccines contain porcine-derived components. Pork is forbidden, or haram, in Islam. Yusran, a forty-six-year-old entrepreneur in Makassar, has not vaccinated any of his five children for precisely this reason. "Even without the vaccine, my children are just fine, thank God; they are healthy," he said. Yet the Indonesian Ulema Council, the country's highest Islamic authority, issued a fatwa in 2018 declaring vaccines permissible for the sake of public health, even those containing porcine gelatine. The religious objection, in other words, has been formally addressed—but the message has not reached everyone.
The government has not been passive. In March, it launched an emergency mass vaccination campaign across roughly one hundred of Indonesia's more than five hundred regencies and cities, including booster shots for more than 220,000 health workers. Officials are partnering with religious organizations to encourage parents to vaccinate their children. Indri Yogyaswari, the director of immunization, reported that measles transmission "has dropped a lot" as a result. But the numbers tell a more sobering story. Last year, the percentage of infants receiving a first dose of the measles-rubella vaccine fell by ten percentage points compared to 2024. Currently, just over three-quarters of children receive both required doses—a figure that falls catastrophically short of the ninety-five percent vaccination rate needed to achieve herd immunity, the threshold at which a disease can no longer spread easily through a population.
Riris Andono Ahmad, an epidemiologist at Gadjah Mada University in Yogyakarta, put it plainly: "Our herd immunity has been compromised." Legislator Putih Sari warned parliament last month that anti-vaccine sentiment has taken root particularly in urban areas, where social media penetration is deepest and misinformation spreads most efficiently. The government's goal is measles eradication by the end of this year. That target now appears out of reach. What remains is a race between a vaccination campaign struggling to overcome entrenched doubt and a virus that needs only the smallest gaps in immunity to find its next host.
Notable Quotes
Posts like that worried me, and it made me think my decision not to vaccinate my children was probably the right one— Fitri Fransiskha, stay-at-home mother in Banten
Even without the vaccine, my children are just fine, thank God; they are healthy— Yusran, entrepreneur in Makassar, who cited halal concerns
The Hearth Conversation Another angle on the story
Why would a mother choose vitamins over a vaccine when measles can kill?
Because she saw her baby get sick once after a shot, and then the internet told her that was proof vaccines are dangerous. One bad experience, multiplied by a thousand posts saying the same thing, becomes a kind of truth.
But the Islamic authorities already said vaccines are permissible. Why hasn't that settled it?
A fatwa from the Ulema Council is one thing. It travels through official channels. Misinformation travels through WhatsApp, TikTok, Instagram—the places where people actually spend their time. The official message has to compete with influencers selling herbal remedies and making money off doubt.
Is this just about religion and social media, or is there something else?
It's also about control. When you give your child vitamins, you're doing something. You're being a good parent. When you trust a vaccine, you're trusting an institution—the government, doctors, a system that may not have earned your trust yet.
The government launched a campaign. Why isn't that working?
It's working somewhat—cases have dropped. But you can't vaccinate your way out of a crisis when three-quarters of children are vaccinated and you need ninety-five percent. You're always one outbreak away from disaster.
What happens next?
Either the campaign reaches more parents and the vaccination rate climbs, or measles keeps circulating. There's no middle ground with herd immunity. You either have it or you don't.