Research published in 2021 found that 65% of antivaccine posts on Facebook and X originated from just 12 individuals.

For years, Facebook has been accused of taking a too-light approach to content moderation. While it's made strides in recent years, problematic content continues to thrive on the company's platforms.

A whistleblower came forward with internal documents showing employees warned leadership about the company's role in fueling political unrest and misinformation. Systems like XCheck shielded high-profile users like President Donald Trump from normal content rules, often to avoid PR backlash.

Accusations of censorship and bias have led social media companies like Meta and X to scale back or abandon moderation tools—just as foreign propaganda surges. Researchers say their ability to track manipulation online has become severely limited.

History tells us the public will tolerate risk of harm from a vaccine if their fear of the disease exceeds their fear of the vaccine.

More than 100 videos, found primarily on Instagram and TikTok in August 2025, promoted products related to beauty, wellness and weight loss. While TikTok removed 94% of content violating its policies on AI-generated content, these deepfakes were watched and shared before removal, undermining public trust in medicine.

A 2023 Nature study showed that exposure to diverse content left participants with unchanged core beliefs, suggesting social media alone cannot create hateful viewpoints. However, such platforms allow rhetoric to spread widely, potentially exacerbating geopolitical tensions.

Before the technology behind vaccinations was discovered, some keen observers of medicine around the globe noticed how previous infections could impact future ones. Learn about the techniques early physicians used before they had vaccines.

Leading up to the 2016 election, misinformation about both Donald Trump, Hillary Clinton, and even Barack Obama flourished on Facebook. In the final stretch leading up to the election, more than one-quarter of Americans visited a fake news site supporting either Trump or Clinton. Many fake news studies have widely different methods of measuring and assessing the impact of fake news, so the actual impact it had in the 2016 election is unclear.

Public health funds and resources that were diverted to COVID-19 response reduced efforts to combat polio and vaccinations for polio and other diseases declined during the pandemic, putting more people at risk for polio.

A vaccine is a medical intervention, and as with any medical intervention, may have side effects. This article discusses side effects and adverse events related to vaccination.

A measles outbreak in the summer of 2025 ultimately led to more than 900 cases and the deaths of two young children. The highly contagious virus requires vaccination rates near 95% to achieve herd immunity—the Texas outbreak spread through areas of significant mistrust of vaccines, including the area’s Mennonite community.

New York Times tech columnist Kevin Roose examines how individuals become radicalized while using platforms like YouTube. Hate crimes that took place before the COVID-19 pandemic inspired the podcast, which looks at online commentators, algorithms, and isolation, and possible explanations for how increased online activity can sometimes lead to violent crime.

The Canadian journal Paediatrics & Child Health issued corrections to 138 case studies published since 2000, acknowledging the cases were entirely fictional—a practice intended to protect patient privacy that was never disclosed to readers. At least 61 of the fabricated reports were cited as fact in other peer-reviewed journals a combined 218 times, including a 2006 Lancet article alleging an infant died from opioid-laced breast milk.

Almost all children likely used to contract poliovirus, but scientists suggest that when infants encountered it very early in life—due to poorer conditions and hygiene—they still had some maternal protection from pregnancy or through breastmilk, so the symptoms were more flu-like.

Though researchers agree that there is a strong genetic component to ASD development, certain environmental factors heighten that risk, with studies suggesting older parents, premature birth, maternal obesity, and air pollution exposure in utero all elevate risks of ASD development. There is no connection between receiving vaccines and ASD development.

Research published in 2021 surveyed how more than 100 kids with food allergies were treated by their peers. About one-third of the surveyed kids had their allergies used against them. Bullying tactics included that their allergens were sometimes intentionally put in their food or thrown at them. Parents usually had no idea this bullying was happening.

Facebook has been criticized for years for a prevalence of disinformation and hate speech, a problem that's not just confined to digital content. The plaintiffs argue Facebook's algorithm amplified dangerous propaganda in Myanmar, contributing to violence.

Cambridge Analytica, a consulting firm with Russian and conservative ties, harvested data from Facebook users through a research tool that tracked interests across social connections on Facebook. Those profiles were used for targeted ad campaigns supporting Donald Trump in 2016 and pro-Brexit ads. A whistleblower originally said the private data of more than 50 million Facebook users was compromised, but a Facebook officer later estimated the number was around 87 million. Facebook settled the class-action lawsuit over the privacy breach for $725M in 2022.

Weakened, live virus vaccines—which aren't offered in the US—carry a risk of virus being shed in the stool. Rarely, the shed virus mutates and leads to vaccine-derived polio infections. Most recent polio cases are genetically linked to those vaccines. As shown in this graphic, there are typically hundreds of vaccine-derived polio cases annually.

As viruses mutate and develop, vaccines have to adapt, leading to regular recommended injections like flu shots. Researchers are working to develop universal vaccines that aim to protect against multiple virus variants if not entire virus families. These vaccines work by creating broadly neutralizing antibodies (bnAbs) that target aspects of viruses that don't typically mutate and are integral to the virus' survival.

There are several different types of vaccines. Each type is designed to teach your immune system how to fight off germs—and the serious diseases they cause. This short overview breaks down the differences between the types.

After influenza B was identified in 1940, researchers created a two-strain vaccine by 1942. The WHO later built a global surveillance system to track mutations, enabling vaccines to be updated annually to target the strains most likely to circulate.