Routine childhood vaccination is now the leading cause of autism, and India is seeing a rapid rise in autism because very young children are receiving ‘too many vaccines.’

FACT: 

Extensive scientific research, including large global studies and reviews by the WHO and CDC, has found no causal link between childhood vaccines and autism.

In recent years, India has seen multiple prominent and influential people either questioning the efficacy and need for vaccines, or casting doubts over its safety. Just a few weeks ago, Sridhar Vembu, chief scientist at Zoho, warned parents that children are being given “way too many vaccines,” and claimed that this is contributing to a “rapid increase in autism in India.”

His social media post, where he shared these concerns, cited a new report circulated on X by Nicolas Hulscher, MPH, Epidemiologist and Administrator at the McCullough Foundation, which asserts that vaccination is “the dominant risk factor” for autism.

In the viral thread, Hulscher describes the report — published by the McCullough Foundation — as the “most comprehensive analysis ever conducted” on autism. He claims the team reviewed over 300 studies and concluded that routine childhood vaccination, especially clustered early-life doses, is the most significant and preventable driver of autism.

Parents should take this analysis seriously. I believe there is increasing evidence that we are giving way too many vaccines to very young children. This is spreading in India too and we are seeing a rapid increase in autism in India. https://t.co/AeiVaieYug

— Sridhar Vembu (@svembu) October 28, 2025

The post lists several proposed risk factors—from older parents and premature birth to environmental toxicants and genetic predispositions—but says vaccines outweigh them all. The report is promoted as a breakthrough that challenges the “biopharmaceutical complex,” and prominently features Andrew Wakefield, the former British doctor, whose infamous 1998 study alleging a link between vaccines and autism was retracted for ethical violations and scientific fraud.

The claims have gained significant traction online, amplified by Vembu’s endorsement. Vembu himself doubled down on the assertions in the next few days, refusing to budge after people called him out for promoting vaccine hesitancy.

Growing vaccine hesitancy and scepticism

Vaccines have often been called the single greatest innovation of the 20th century. The World Health Organization estimated that in the 50 years since 1974, vaccines have saved 15.4 crore lives. “That’s six lives a minute, every day, for five decades,” it elaborated.

Yet, sceptics continue to peddle conspiracy theories that these lifesaving interventions could, in fact, cause harm, most notably, it causes autism. Earlier this year, US Health Secretary Robert F. Kennedy Jr. made almost identical claims during an appearance on The Tucker Carlson Show. Kennedy alleged that vaccines, particularly the hepatitis B shot given in early infancy, dramatically increase the risk of autism. These were debunked earlier too.

In the video, Kennedy cited a 1999 analysis he attributed to CDC researcher Thomas Verstraeten, claiming the study found an “11,135 per cent elevated risk of autism” in children who received the hepatitis B vaccine within the first 30 days of life compared to those who were vaccinated later or not at all. He further alleged that the CDC “kept the study secret” and manipulated it across multiple versions to hide a supposed vaccine–autism link.

Kennedy also asserted that “over a hundred studies” in the broader scientific literature support his position, echoing the same narrative now circulating through the McCullough Foundation report shared by Nicolas Hulscher and amplified by Sridhar Vembu.

The same claim was even echoed by US president Donald Trump in the past. “Healthy young child goes to doctor, gets pumped with massive shot of many vaccines, doesn’t feel good and changes – AUTISM. Many such cases!,” Trump tweeted in 2014.

In India, too, earlier this year, a prominent CEO and YouTuber falsely claimed that vaccines are possibly reducing lifespan as well.

Such unsubstantiated claims by prominent and influential persons, coupled with policy decisions such as the US’ National Institute of Health cutting funds meant for research into vaccine hesitancy and removing vaccines from recommended schedules, have compounded the issue of vaccine hesitancy, with devastating consequences.

“Outbreaks of vaccine-preventable diseases such as measles, meningitis and yellow fever are rising globally, and diseases like diphtheria, that have long been held at bay or virtually disappeared in many countries, are at risk of re-emerging,” according to the WHO, which added that “the number of children missing routine vaccinations has been increasing in recent years, even as countries make efforts to catch up children missed during the pandemic.”

“In 2023, an estimated 14.5 million children missed all of their routine vaccine doses – up from 13.9 million in 2022 and 12.9 million in 2019,” it said.

So what are the facts?

The assertion that vaccines cause autism gained traction in the 1990s, when London-based physician Andrew Wakefield and others published in the Lancet that they had found a link between the measles, mumps and rubella (MMR) vaccine and autism. The study was later exposed as flawed and unethical, and was retracted by Lancet in 2010. The study’s retraction and Wakefield’s loss of medical license underscored the gravity of his misconduct, yet the debate lingered in public discourse.

Numerous large-scale studies have since debunked the purported vaccine-autism link. A Danish study of over 537,000 children found no increased autism risk among MMR-vaccinated individuals. Similarly, a 2019 study involving nearly 660,000 children corroborated these findings. The WHO has emphatically stated that extensive research disproves any causal relationship between vaccines and autism, emphasising that correlation does not imply causation in this context.

Thimerosal, a mercury-based preservative in some vaccines, also became a focal point of concern in online discussions. However, multiple studies, including those conducted by the Centers for Disease Control and Prevention, found no evidence linking thimerosal to autism. The preservative’s removal from most childhood vaccines in the early 2000s did not affect rising autism rates, further disproving any connection claimed on social platforms.

Autism spectrum disorder is now recognized as a complex condition influenced by genetic and environmental factors. Research suggests that 60-90 per cent of autism risk is attributable to genetics, with environmental influences like parental age or prenatal exposures potentially playing a role. However, these factors are not directly linked to vaccinations, contrary to what such social media posts and statements might suggest.

The scientific consensus firmly establishes that childhood vaccinations do not cause autism. This conclusion is based on extensive research that has consistently disproven any causal relationship. Vaccination remains a crucial public health measure, preventing serious diseases and fostering community protection through herd immunity. The initial claims, rooted in flawed research and often propagated on social media, have been thoroughly and repeatedly discredited, reinforcing the safety and efficacy of immunization programmes.

Also read: Gavi hits HPV vaccine goal, reaching 86 million girls worldwide