The news of a rare clotting problem associated with the Johnson and Johnson COVID-19 vaccine temporarily disrupted the plans of many Americans, but its biggest impact may be felt abroad. The United States has already administered 124 million COVID-19 vaccine doses, of which the J&J shot accounts for just five percent, and the country has plenty of alternatives to cover its entire population. In dozens of other nations, however, options are few beyond the J&J vaccine and another made by AstraZeneca that shares similar technology and apparent risks.

Both the J&J and the AstraZeneca vaccines use adenovirus-vector technology. These vaccines are less expensive, more stable, and easier to distribute than their mRNA-based counterparts from Moderna and Pfizer-BioNTech. The J&J vaccine requires just one dose, an advantage for transient populations. The multinational COVID-19 Vaccine Global Access program, or COVAX, secured more than one billion doses for distribution this year, and nearly 80 percent of them are from J&J, AstraZeneca, or an Indian manufacturer producing the AstraZeneca vaccine. One hundred eighty countries are relying on shipments of the AstraZeneca vaccine, known to some as “the people’s vaccine,” by the end of 2021. Dozens of other nations have turned to Russia’s Sputnik V vaccine and China’s CanSino vaccine, which are also based on adenovirus-vector technology.

On April 13, the U.S. Food and Drug Administration (FDA) announced a pause in the use of the J&J vaccine, and the Dominican Republic, South Africa, and several European countries quickly followed suit. Russia raced to issue a statement noting the differences between the J&J shot and the Sputnik V vaccine and asserting that it had received no reports of similar blood clots. Although the EU will resume using the J&J vaccine with a warning to those in high-risk groups, it also announced plans to concentrate new purchases on non-adenovirus-vector vaccines, working to acquire 1.8 billion doses of the Pfizer-BioNTech mRNA vaccine for 2022 and 2023 and betting on the new technology to address the possible need for booster and second-generation COVID-19 vaccines.

Ten days later, the United States announced that it would resume vaccinating with the J&J vaccine, adding a warning about the risk of the clotting disorder. South Africa had made a similar decision a day earlier.

Countries necessarily make regulatory and purchasing decisions based on the specific needs of their populations. But these decisions can have far-reaching consequences for the availability and uptake of vaccines globally—and, ultimately, for progress toward ending the pandemic for all. The apparently unique association between the adenovirus-vector vaccine platform and a rare but potentially fatal risk suggests that concerns about safety will continue. Limiting the unintended consequences of regulatory decisions will mean adopting a more equitable approach to manufacturing, distributing, and monitoring vaccines.

Risks and Benefits

Now is not the first time that U.S. regulators have grappled with a decision on vaccines that could have outsize international consequences. In 2010, the presence of unexpected material in vaccine vials led the FDA to recommend a pause in the U.S. use of GlaxoSmithKline’s vaccine against rotavirus, an infection that causes severe diarrhea and is treatable in the United States but lethal to hundreds of thousands of children each year in poor nations with limited health infrastructure.

To address the potential global fallout at the time, the FDA made clear in its communication that while it was suspending the use of the vaccine in the United States, the calculation of the vaccine’s risks and benefits could well be different in countries where rotavirus caused deaths more frequently. The announcement was closely coordinated with global health organizations. The vaccination pause proved to be brief, with little damage to vaccine confidence. Coverage rates for rotavirus vaccination have risen globally since 2010, according to World Health Organization data.

With COVID-19 vaccines, it is again important for federal health officials in the United States to keep the world in mind, even as it is their first responsibility to make sure that U.S. vaccines are safe and effective. The United States can work with global regulators and public health authorities in other countries to promote consistent messaging and contextualize the risks and benefits for a global audience. As health officials calculate the risks of certain vaccines for the U.S. population, for example, they can develop parallel assessments applicable to places with different rates of infection and death or with less access to alternate vaccines in the near term. Doing so will support the decision-making of local regulators outside the United States.

At the same time, the United States should bolster safety surveillance in other countries. When any vaccine is given to millions of people worldwide, very rare adverse effects will emerge that should be transparently and rigorously assessed. In late December, the World Health Organization released guidelines on how to collect, analyze, and share safety data for COVID-19 vaccines, but few nations have the money, systems, or trained health-care workers to put that guidance into practice. Without adequate safety monitoring and reporting in many countries, the frequency of rare adverse events is difficult to evaluate—and not just from the J&J and AstraZeneca vaccines but also from those for which far less data is available, including Sputnik V and CanSino.

Global Warp Speed

Fundamentally, to have one type of vaccine for select countries and another for the rest of the world entails risk. The United States and its allies must do more to expand the global production and availability of additional types of COVID-19 vaccines, particularly those involving mRNA technology. In most of the world, there are simply not enough doses available to meet the continuing need, much less to shift strategies when safety concerns arise. The United States' own experience has demonstrated that government support, through both policy and financing, is necessary in order to quickly ramp up vaccine manufacturing to meet the pandemic demand.

A similar effort to the American one but on an international scale—a global Operation Warp Speed of sorts—is needed to accomplish what U.S. cash donations alone simply cannot. Governments and development finance institutions should mobilize unused manufacturing capacity, overcome barriers to technology transfer, and convince firms to redeploy vaccine supplies and raw materials that had been reserved for projects that did not pan out. These efforts could help create a geographically distributed vaccine manufacturing network that can scale up and adjust to respond to variants of this coronavirus as well as to future pandemic threats.

The stakes of vaccine confidence are very high, with COVID-19 infections surging across the globe at a clip of more than 700,000 new cases per day. As concerns arise about side effects, public health agencies have to move quickly to access data, assess risks, make clear decisions, and explain those decisions to the public. In doing so, these agencies must work together.

During a global pandemic, no country makes decisions about how to vaccinate its public in a vacuum. The recent news about adenovirus-vector vaccines is a wake-up call that better global coordination and greater capacity will be needed to fight a common enemy.

UPDATE APPENDED (April 24, 2021)

This article has been updated to reflect the fact that the CDC has recommended resuming use of the J&J vaccine.

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  • THOMAS J. BOLLYKY is Director of the Global Health Program at the Council on Foreign Relations.
  • JENNIFER NUZZO is a Senior Scholar at the Johns Hopkins Center for Health Security, an Associate Professor at the Johns Hopkins Bloomberg School of Public Health, and Senior Fellow for Global Health at the Council on Foreign Relations.
  • JOSHUA SHARFSTEIN is Professor of the Practice in Health Policy and Management at the Johns Hopkins Bloomberg School of Public Health.
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