FDA claims on COVID-19 vaccine safety are unsupported by reliable data – and could severely hinder vaccine access

Frank Han, University of Illinois Chicago The Food and Drug Administration is seeking to drastically change procedures for testing vaccine safety and approving vaccines, based on unproven claims that mRNA-based COVID-19 vaccines caused the death of at least 10 children. The agency detailed its plans in a memo released to staff on Nov. 28, 2025, which was obtained by several news outlets and published by The Washington Post. Citing an internal, unpublished review, the memo, written by the agency’s top vaccine regulator, Vinay Prasad, attributes the children’s deaths to myocarditis, an inflammation of the heart muscle. And it says the deaths were reported to the Vaccine Adverse Event Reporting System, or VAERS, but provides no evidence that the vaccines caused the deaths.  

COVID-19 vaccine safety

The death of children due to an unsafe vaccine is a serious allegation. I am a pediatric cardiologist who has studied the link between COVID-19 vaccines and heart-related side effects such as myocarditis in children. To my knowledge, studies to date have shown such side effects are rare, and severe outcomes even more so. However, I am open to new evidence that could change my mind. But without sufficient justification and solid evidence, restricting access to an approved vaccine and changing well-established procedures for testing vaccines would carry serious consequences. These moves would limit access for patients, create roadblocks for companies and worsen distrust in vaccines and public health. In my view, it’s important for people reading about these FDA actions to understand how the evidence on a vaccine’s safety is generally assessed.

Determining cause of death

The FDA memo claims that the deaths of these children were directly related to receiving a COVID-19 immunization. From my perspective as a clinician, it is awful that any child should die from a routine vaccination. However, health professionals like me owe it to the public to uphold the highest possible standards in investigating why these deaths occurred. If the FDA has evidence demonstrating something that national health agencies worldwide have missed – widespread child deaths due to myocarditis caused by the COVID-19 vaccine – I don’t doubt that even the most pro-vaccine physician will listen. So far, however, no such evidence has been presented. While a death logged in VAERS is a starting point, on its own it is insufficient to conclude whether a vaccine caused the death or other medical causes were to blame. To demonstrate a causal link, FDA staff and physicians must align the VAERS report with physicians’ assessments of the patient, as well as data from other sources for monitoring vaccine safety. These include PRISM, which logs insurance claims data, and the Vaccine Safety Datalink, which tracks safety signals in electronic medical records. It’s known that most deaths logged only in VAERS of children who recently received vaccines have been incorrectly attributed to the vaccines – either by accident or in some cases on purpose by anti-vaccine activists.

Heart-related side effects of COVID-19 vaccines

In his Substack and Twitter accounts, Prasad has said that he believes the rate of severe cardiac side effects after COVID-19 vaccination is severely underestimated and that the vaccines should be restricted far more than they currently are. In a July 2025 presentation, Prasad quoted a risk of 27 cases per million of myocarditis in young men who received the COVID-19 vaccine. A 2024 review suggested that number was a bit lower – about 20 cases out of 1 million people. But that same study found that unvaccinated people had greater risk of heart problems after a COVID-19 infection than vaccinated people. In a different study, people who got myocarditis after a COVID-19 vaccination developed fewer complications than people who got myocarditis after a COVID-19 infection. Existing vaccine safety infrastructure in the U.S. successfully identifies dangers posed by vaccines – and did so during the COVID-19 pandemic. Today, most COVID-19 vaccines in the U.S. rely on mRNA technology. But as vaccines were first emerging during the COVID-19 pandemic, two pharmaceutical companies, Janssen and AstraZeneca, rolled out a vaccine that used a different technology, called a viral vector. This type of vaccine had a very rare but genuine safety problem that was detected.

VAERS, the Vaccine Safety Datalink, clinical investigators in the U.S. and their European counterparts detected that these vaccines did turn out to cause blood clotting. In April 2021, the FDA formally recommended pausing their use, and they were later pulled from the market. Death due to myocarditis from COVID-19 vaccination is exceedingly rare. Demonstrating that it occurred requires proof that the person had myocarditis, evidence that no other reasonable cause of death was present, and the absence of any additional cause of myocarditis. These factors cannot be determined from VAERS data, however – and to date, the FDA has presented no other relevant data.

A problematic vision for future vaccine approvals

Currently, vaccines are tested both by seeing how well they prevent disease and by how well they generate antibodies, which are the molecules that help your body fight viruses and bacteria. Some vaccines, such as the COVID-19 vaccine and the influenza vaccine, need to be updated based on new strains. The FDA generally approves these updates based on how well the new versions generate antibodies. Since the previous generation of vaccines was already shown to prevent infection, if the new version can generate antibodies like the previous one, researchers assume its ability to prevent infection is comparable too. Later studies can then test how well the vaccines prevent severe disease and hospitalization. The FDA memo says this approach is insufficient and instead argues for replacing such studies with many more placebo-controlled trials – not just for COVID-19 vaccines but also for widely used influenza and pneumonia vaccines. That may seem reasonable theoretically. In practice, however, it is not realistic. Today’s influenza vaccines must be changed every season to reflect mutations to the virus. If the FDA were to require new placebo-controlled trials every year, the vaccine being tested would become obsolete by the time it is approved. This would be a massive waste of time and resources.

Also, detecting vaccine-related myocarditis at the low rate at which it occurs would have required clinical trials many times larger than the ones that were done to approve COVID-19 mRNA vaccines. This would have cost at least millions of dollars more, and the delay in rolling out vaccines would have also cost lives. Placebo-controlled trials would require comparing people who receive the updated vaccine with people who remain unvaccinated. When an older version of the vaccine is already available, this means purposefully asking people to forgo that vaccine and risk infection for the sake of the trial, a practice that is widely considered unethical. Current scientific practice is that only a brand-new vaccine may be compared against placebo. While suspected vaccine deaths should absolutely be investigated, stopping a vaccine for insufficient reasons can lead to a significant drop in public confidence. That’s why it’s essential to thoroughly and transparently investigate any claims that a vaccine causes harm.

Vaccine vs illness

To accurately gauge a vaccine’s risks, it is also crucial to compare its side effects with the effects of the illness it prevents. For COVID-19, data consistently shows that the disease is clearly more dangerous. From Aug. 1, 2021, to July 31, 2022, more than 800 children in the U.S. died due to COVID-19, but very few deaths from COVID-19 vaccines in children have been been verified worldwide. What’s more, the disease causes many more heart-related side effects than the vaccine does. Meanwhile, extensive evidence shows that COVID-19 vaccination reduces the risk of hospitalization by more than 70% and the risk of severe illness in adolescent children by 79%. Studies also show it dramatically reduces their risk of developing long COVID, a condition in which symptoms such as extreme fatigue or weakness persist more than three months after a COVID-19 infection. Reporting only the vaccines’ risks, and not their benefits, shows just a small part of the picture. Frank Han, Assistant Professor of Pediatric Cardiology, University of Illinois Chicago This article is republished from The Conversation under a Creative Commons license. Read the original article.

Kent Jones, Babson College The U.S. Supreme Court is currently reviewing a case to determine whether President Donald Trump’s global tariffs are legal. Until recently, tariffs rarely made headlines. Yet today, they play a major role in U.S. economic policy, affecting the prices of everything from groceries to autos to holiday gifts, as well as the outlook for unemployment, inflation and even recession. I’m an economist who studies trade policy, and I’ve found that many people have questions about tariffs. This primer explains what they are, what effects they have, and why governments impose them.

What are tariffs, and who pays them?

Tariffs are taxes on imports of goods, usually for purposes of protecting particular domestic industries from import competition. When an American business imports goods, U.S. Customs and Border Protection sends it a tariff bill that the company must pay before the merchandise can enter the country. Because tariffs raise costs for U.S. importers, those companies usually pass the expense on to their customers by raising prices. Sometimes, importers choose to absorb part of the tariff’s cost so consumers don’t switch to more affordable competing products. However, firms with low profit margins may risk going out of business if they do that for very long. In general, the longer tariffs are in place, the more likely companies are to pass the costs on to customers. Importers can also ask foreign suppliers to absorb some of the tariff cost by lowering their export price. But exporters don’t have an incentive to do that if they can sell to other countries at a higher price. Studies of Trump’s 2025 tariffs suggest that U.S. consumers and importers are already paying the price, with little evidence that foreign suppliers have borne any of the burden. After six months of the tariffs, importers are absorbing as much as 80% of the cost, which suggests that they believe the tariffs will be temporary. If the Supreme Court allows the Trump tariffs to continue, the burden on consumers will likely increase. While tariffs apply only to imports, they tend to indirectly boost the prices of domestically produced goods, too. That’s because tariffs reduce demand for imports, which in turn increases the demand for substitutes. This allows domestic producers to raise their prices as well.

A brief history of tariffs

The U.S. Constitution assigns all tariff- and tax-making power to Congress. Early in U.S. history, tariffs were used to finance the federal government. Especially after the Civil War, when U.S. manufacturing was growing rapidly, tariffs were used to shield U.S. industries from foreign competition. The introduction of the individual income tax in 1913 displaced tariffs as the main source of U.S. tax revenue. The last major U.S. tariff law was the Smoot-Hawley Tariff Act of 1930, which established an average tariff rate of 20% on all imports by 1933. Those tariffs sparked foreign retaliation and a global trade war during the Great Depression. After World War II, the U.S. led the formation of the General Agreement on Tariffs and Trade, or GATT, which promoted tariff reduction policies as the key to economic stability and growth. As a result, global average tariff rates dropped from around 40% in 1947 to 3.5% in 2024. The U.S. average tariff rate fell to 2.5% that year, while about 60% of all U.S. imports entered duty-free. While Congress is officially responsible for tariffs, it can delegate emergency tariff power to the president for quick action as long as constitutional boundaries are followed. The current Supreme Court case involves Trump’s use of the International Emergency Economic Powers Act, or IEEPA, to unilaterally change all U.S. general tariff rates and duration, country by country, by executive order. The controversy stems from the claim that Trump has overstepped his constitutional authority granted by that act, which does not mention tariffs or specifically authorize the president to impose them.

The pros and cons of tariffs

In my view, though, the bigger question is whether tariffs are good or bad policy. The disastrous experience of the tariff war during the Great Depression led to a broad global consensus favoring freer trade and lower tariffs. Research in economics and political science tends to back up this view, although tariffs have never disappeared as a policy tool, particularly for developing countries with limited sources of tax revenue and the desire to protect their fledgling industries from imports. Yet Trump has resurrected tariffs not only as a protectionist device, but also as a source of government revenue for the world’s largest economy. In fact, Trump insists that tariffs can replace individual income taxes, a view contested by most economists. Most of Trump’s tariffs have a protectionist purpose: to favor domestic industries by raising import prices and shifting demand to domestically produced goods. The aim is to increase domestic output and employment in tariff-protected industries, whose success is presumably more valuable to the economy than the open market allows. The success of this approach depends on labor, capital and long-term investment flowing into protected sectors in ways that improve their efficiency, growth and employment. Critics argue that tariffs come with trade-offs: Favoring one set of industries necessarily disfavors others, and it raises prices for consumers. Manipulating prices and demand results in market inefficiency, as the U.S. economy produces more goods that are less efficiently made and fewer that are more efficiently made. In addition, U.S. tariffs have already resulted in foreign retaliatory trade actions, damaging U.S. exporters. Trump’s tariffs also carry an uncertainty cost because he is constantly threatening, changing, canceling and reinstating them. Companies and financiers tend to invest in protected industries only if tariff levels are predictable. But Trump’s negotiating strategy has involved numerous reversals and new threats, making it difficult for investors to calculate the value of those commitments. One study estimates that such uncertainty has actually reduced U.S. investment by 4.4% in 2025. A major, if underappreciated, cost of Trump’s tariffs is that they have violated U.S. global trade agreements and GATT rules on nondiscrimination and tariff-binding. This has made the U.S. a less reliable trading partner. The U.S. had previously championed this system, which brought stability and cooperation to global trade relations. Now that the U.S. is conducting trade policy through unilateral tariff hikes and antagonistic rhetoric, its trading partners are already beginning to look for new, more stable and growing trade relationships. So what’s next? Trump has vowed to use other emergency tariff measures if the Supreme Court strikes down his IEEPA tariffs. So as long as Congress is unwilling to step in, it’s likely that an aggressive U.S. tariff regime will continue, regardless of the court’s judgment. That means public awareness of tariffs ⁠– and of who pays them and what they change ⁠– will remain crucial for understanding the direction of the U.S. economy. Kent Jones, Professor Emeritus, Economics, Babson College This article is republished from The Conversation under a Creative Commons license. Read the original article.