In today’s digital world, a dramatic image can travel around the globe in a matter of hours. A striking picture, an alarming headline, and a few carefully chosen words are often enough to convince thousands—or even millions—of people that something shocking has happened before they have a chance to verify the facts.

Recently, social media has seen a surge in posts claiming that people who received COVID-19 vaccines are developing “new cancers” or experiencing widespread heart damage. Many of these posts feature emotionally charged visuals, such as hearts pierced by syringes, urgent warning labels, or frightening before-and-after images designed to provoke fear.

While these images can be persuasive, they are not evidence.

Medical experts consistently emphasize that extraordinary health claims require strong scientific evidence. A dramatic photograph or viral caption may attract attention, but it cannot establish that one event caused another. Determining whether a vaccine, medication, or illness contributes to a medical condition requires carefully designed research involving large groups of people and ongoing safety monitoring.

Since COVID-19 vaccines became available, researchers and public health agencies around the world have continued to monitor their safety. Millions of people have participated in clinical trials and vaccination programs, providing an unprecedented amount of data for scientists to analyze.

Like any medical product, COVID-19 vaccines can cause side effects. Most are mild and temporary, such as soreness at the injection site, fatigue, headache, or a low-grade fever that resolves within a few days.

Researchers have also identified some rare but important adverse events. For example, certain COVID-19 vaccines have been associated with uncommon cases of myocarditis or pericarditis—conditions involving inflammation of the heart muscle or the surrounding tissue. These events have been observed most often in younger males after specific vaccine types and are considered rare. Most affected individuals recover with appropriate medical care.

Recognizing these rare events demonstrates that vaccine safety systems are working as intended. Health authorities continuously collect reports, investigate potential concerns, and update recommendations when new evidence becomes available.

However, this is very different from claiming that vaccines broadly “cause heart disease” or that they are creating a widespread cancer epidemic.

At present, there is no credible scientific evidence showing that authorized COVID-19 vaccines cause cancer or trigger a new form of cancer in vaccinated people.

Cancer develops through complex biological processes involving genetic changes, environmental exposures, lifestyle factors, aging, and, in some cases, inherited risk. Scientists continue to study cancer extensively, but current evidence does not support the claim that COVID-19 vaccines initiate cancer.

One reason misleading claims spread so easily is that timing alone can be confusing.

Every day, people are diagnosed with heart disease, cancer, diabetes, autoimmune disorders, and many other illnesses. Because billions of COVID-19 vaccine doses have been administered worldwide, some individuals will inevitably develop unrelated medical conditions after vaccination simply by coincidence.

Scientists distinguish between events that occur after vaccination and those that are caused by vaccination. Establishing causation requires careful comparison between vaccinated and unvaccinated populations while accounting for age, medical history, and other risk factors.

This is why peer-reviewed studies and ongoing surveillance are so important.

Another factor contributing to confusion is the use of emotionally powerful imagery.