Pfizer (Finally) Publishes the List of Side Effects of Its Vaccines

What You Need to Know About Safety, Transparency, and What This Really Means

In recent months, a claim has circulated online that pharmaceutical giant Pfizer has “finally published a list of side effects” for its COVID‑19 vaccines—almost as if this information was previously hidden or secret. Some posts have presented supposedly explosive lists of hundreds of conditions allegedly tied to vaccination. Others have implied that the company only now revealed what it knew all along.

But before jumping to conclusions, it’s important to examine what has actually happened—and what reputable data truly show.

This blog post will explore:

• What Pfizer has and has not published

• How vaccine side effects are identified and reported

• The difference between adverse events and confirmed side effects

• What scientists and regulators say about COVID‑19 vaccine safety

• Why transparency matters

• How to interpret safety data responsibly

By the end, you’ll have a clear understanding of the facts without exaggeration or misinformation.

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What People Are Talking About Online

Some social media posts claim that Pfizer released a massive list of side effects—including hundreds of serious conditions—only after legal or public pressure. These lists are often shared as proof that vaccines are dangerous and that companies were hiding risks.

For example, documents circulating online include lists of conditions like “cardiac arrest,” “brainstem thrombosis,” “stillbirth,” and “sudden death,” presented as if they are confirmed vaccine side effects. Pulmonary Fibrosis News

However, independent fact checks have repeatedly shown that these claims are false or misleading:
✔️ Pfizer has published safety data and documented known side effects in its clinical trial and safety information.
❌ There has been no sudden or secret release of a new “explosive list” of side effects in 2025. AFP Fact Check+2The Times of India+2

So what has been published, and how should it be interpreted? Let’s break it down.

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What Pfizer Actually Publishes

Clinical Trial Data and Safety Sheets

When Pfizer’s COVID‑19 vaccines (such as COMIRNATY®) were tested in clinical trials, the company submitted large volumes of safety data to regulatory authorities like the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA). These data include:

• Common side effects seen during trials

• Rare or serious reactions that were observed

• Recommendations for monitoring after vaccination

For example, official safety information includes side effects such as:

• Injection site pain

• Fatigue

• Headache

• Muscle pain

• Chills

• Joint pain

• Fever

• Swelling or redness at the injection site

• Nausea

• Swollen lymph nodes (lymphadenopathy)

• Severe allergic reactions (rare)

• Myocarditis and pericarditis (rare heart inflammation) pfizer.com+1

These side effects are documented by Pfizer in safety fact sheets provided to healthcare providers and individuals receiving the vaccine.

Post‑Marketing Safety Data

Once vaccines are authorized and distributed broadly, regulators continue to collect safety data from millions or billions of doses administered. This process is called post‑marketing surveillance.

In this context, Pfizer and regulators may note adverse reactions that have been reported, but importantly:

A report does not automatically prove causation.
"Adverse events" are anything that happens after vaccination, whether or not the vaccine caused them. Science Feedback

For example, if someone experiences an unrelated illness after vaccination, it may be reported, but that doesn’t mean the vaccine caused it.

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The Difference Between Adverse Events and Confirmed Side Effects

This distinction is crucial but often misunderstood.

📌 Adverse Events

These are any health problems that occur after vaccination and are reported to surveillance systems. They may or may not be caused by the vaccine.

People are encouraged to report all health changes after vaccination so regulators can investigate patterns. This includes conditions unrelated to the vaccine.

📌 Confirmed Side Effects

These are reactions that:

• Occur more frequently in vaccinated people than unvaccinated people

• Have been verified through scientific analysis to be caused by the vaccine

For example, clinical studies and surveillance data have confirmed that certain reactions occur at small rates after mRNA COVID‑19 vaccination, such as:

• Myocarditis and pericarditis in young males (rare)

• Severe allergic reactions (very rare)

These confirmed side effects are included in official vaccine safety profiles and updated via regulatory advisories. Drugs.com

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Scientific and Regulatory Transparency

Regulatory Oversight

Regulatory agencies—including the FDA and EMA—require that vaccine makers disclose safety data as part of the authorization process. These data are reviewed by independent scientists.

The FDA has also issued updated warning information based on ongoing safety monitoring. In 2025, for instance, the FDA ordered updated warnings regarding myocarditis and pericarditis risk, particularly in males ages 16–25. CBS News

These updates reflect transparency and ongoing evaluation, not a sudden or covert release of unknown dangers.

Independent Analysis

Safety monitoring isn’t just done by Pfizer. Independent researchers, public health agencies, and academic institutions continuously analyze data to identify patterns and verify safety profiles.

For example, international studies involving millions of people worldwide have quantified known rare side effects while also confirming overall vaccine safety. FactCheck.org

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So Why Do People Think There’s a New “List”?

Several factors contribute to misunderstandings:

1. Misinterpreting Adverse Event Lists

Some documents list adverse events of special interest—categories that researchers monitor closely—not confirmed vaccine side effects. Reddit

These lists are part of safety monitoring frameworks, not “hidden danger lists.”

2. Viral Misinformation

Posts online often take partial or decontextualized data and present it as shocking revelations. Independent fact‑checking has shown many such claims are false. thedispatch.com

3. Confusion About Reporting Systems

Systems like VAERS (Vaccine Adverse Event Reporting System) collect broad reports without establishing cause. This can be misread as a list of confirmed vaccine effects.

Understanding these systems is essential for interpreting data responsibly.

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What the Data Really Say

Very Common Side Effects

Common, expected reactions reported after mRNA COVID‑19 vaccines include:

• Pain at the injection site

• Fatigue

• Headache

• Muscle pain

• Chills

• Fever

• Joint pain

• Nausea

• Swelling/redness at the injection site

These reactions are typically mild to moderate and resolve on their own, often within a few days. pfizer.com

Rare Confirmed Side Effects

Regulators have identified rare but confirmed side effects such as:

• Myocarditis and pericarditis: Inflammation of the heart muscle or its lining, most commonly in young males, usually mild and resolving. Drugs.com

• Severe allergic reactions: Very rare, which is why monitoring after vaccination is recommended. pfizer.com

These associations are based on careful epidemiological analysis—not speculation.

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The Importance of Context and Risk

When discussing vaccine side effects, context matters.

Risk vs Benefit

Millions of people worldwide have received COVID‑19 vaccines. The vast majority experience only mild reactions. Serious side effects are extremely rare compared with the risks of COVID‑19 itself—such as hospitalizations, long‑term health effects, and death.

This context is essential for informed decisions.

Why Transparency Matters

Public trust in vaccines depends on clear communication about both benefits and risks. Regulatory requirements ensure that safety data is reviewed by independent experts and shared in official documents and advisories.

There is no credible evidence that Pfizer secretly withheld safety information.

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How to Evaluate Claims About Vaccine Safety

When encountering dramatic claims online, ask:

✅ Is the source reputable and transparent?
✅ Is the claim backed by data from health authorities or peer‑reviewed research?
✅ Does the claim distinguish between adverse events and confirmed side effects?
✅ Are statistics and context provided?

Reliable information comes from official health agencies, scientific publications, and fact‑checked reporting—not unverified social posts.

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Final Thoughts

Pfizer has not suddenly published a hidden list of secret side effects.

What is true and verifiable is that:

• Vaccine safety data has always been provided to regulators as part of authorization.

• Common side effects are well documented and widely known.

• Rare confirmed side effects are recognized by health agencies and clearly communicated.

• Adverse events reporting systems exist to ensure ongoing monitoring—but they are not proof of causation. AFP Fact Check+1

Understanding the difference between anecdote, report, and confirmed safety data is critical for responsible health decisions.

Good science and transparency go hand in hand—and in this case, they show that public access to vaccine safety information has been ongoing, not sudden or hidden.