For the first time since the COVID-19 pandemic began, the World Health Organization may be on the cusp of declaring a different disease threat—monkeypox—to be a public health emergency of international concern. There are now more than 3,500 confirmed cases in the latest monkeypox epidemic, which has expanded steadily across 44 countries over the past ten weeks. Yesterday, a WHO emergency committee met in Geneva to discuss the epidemic, and some experts anticipate it will advise WHO Director General Tedros Adhanom Ghebreyesus to make the emergency declaration.

Monkeypox and SARS-CoV-2, the virus that causes COVID-19, may both constitute international public health emergencies, but they are very different pathogens. Monkeypox is an older virus. It belongs to the orthopox family of viruses, which also includes smallpox. It spreads less efficiently than SARS-CoV-2, kills fewer people (no one so far outside of endemic countries in Africa), and poses its greatest threat to young children, pregnant women, and people who are immunosuppressed. The monkeypox virus spreads mainly through close contact, with the current outbreak occurring mostly among men who have sex with men, but it is now starting to expand beyond that population.

The biggest difference between the two pathogens may be that for monkeypox, unlike for the novel coronavirus, there were already tools to combat the virus when it emerged. A polymerase chain reaction (PCR) diagnostic test for monkeypox already exists, although the U.S. Centers for Disease Control and Prevention has again been slow to expand access to it, as happened with the PCR test for COVID-19. And although monkeypox patients generally require only supportive care, there is a smallpox treatment in U.S. stockpiles that may work against monkeypox in patients who develop more severe disease. There are also two vaccines against smallpox that could be used against monkeypox. The U.S. government—through the Biomedical Advanced Research and Development Authority (BARDA)—funded the development of MVA-BN (known as Jynneos in the United States), a two-dose vaccine that was originally developed for smallpox but is effective against monkeypox and is the only vaccine that the U.S. Food and Drug Administration has authorized specifically for that use. Bavarian Nordic, a Denmark-based manufacturer, makes the vaccine; supplies are extremely limited, and the vaccine is costly. The other vaccine, ACAM2000, has a higher risk of producing more serious adverse events and is not suitable for mass immunization.

The WHO does not currently recommend mass vaccination for monkeypox but calls instead for using MVA-BN to vaccinate close contacts of monkeypox patients and health workers at risk of exposure. It is an open question whether this strategy will help slow the spread of the outbreak. Time is of the essence since MVA-BN has not yet been proved to be effective in a single dose, and the two doses are supposed to be administered four weeks apart. Forcing close contacts to wait for a second dose would require broader behavioral change to prevent the spread of infection.

Meanwhile, even this limited WHO-recommended approach would still require vaccine supplies. This raises the key question of whether the monkeypox epidemic will be different from COVID-19 in one last way: will doses go where they can do the most good by disrupting transmission, preventing deaths, and stopping other severe outcomes? Or, in a rerun of what occurred during the COVID-19 pandemic, will wealthy nations buy and stockpile available supplies in advance?

As the COVID-19 pandemic progressed, many world leaders professed to regret the deeply inequitable vaccine distribution that resulted when a few countries bought up early supplies and failed to sufficiently support international distribution. Monkeypox is an immediate test of whether these countries have learned the lessons of COVID-19—especially that, in the end, vaccine nationalism hurts everyone and only prolongs international public health emergencies. So far, the report card has been less than satisfactory.


Bavarian Nordic is a relatively small vaccine manufacturer, and the limited supplies of its MVA-BN vaccine are already disappearing fast. Five days after the monkeypox outbreak began, the United States exercised its option to purchase an additional 500,000 doses, on top of the 1.4 million doses already in the U.S. stockpile. On June 14, the European Union signed a deal with Bavarian Nordic for the supply of 109,090 doses of MVA-BN, even though the European Medicines Agency has yet to authorize the vaccine for use against monkeypox. Germany has purchased 40,000 doses and reserved an option for 200,000 more. France is already vaccinating with MVA-BN and Denmark, Spain, and the United Kingdom have likewise announced purchases. Exactly how many MVA-BN doses are left to buy remains unclear, but there are signs that current supplies may be running short. Canada, which recently signed a $56 million contract with Bavarian Nordic for MVA-BN vaccines, will have to wait until 2023 for its first deliveries to arrive.

The WHO has urged its member countries to work together to ensure monkeypox vaccine supplies are “made available adequately and equitably,” including “to countries with limited/no vaccine supply.” The organization says it will establish coordination mechanisms to make vaccines available where needed, as it tried to do with COVID-19.

Maximizing the potential of scarce vaccine supplies against monkeypox in this epidemic depends on doses going where they can do the most good. But there is currently no consensus on where that would be.

Monkeypox is an immediate test of whether wealthy countries have learned the lessons of COVID-19.

One strategy would be using scarce vaccines to control the spread of the monkeypox epidemic outside of settings where the virus has traditionally been endemic. Uncontrolled global spread increases the likelihood that the virus will acquire new mutations that make it more transmissible or deadly, and that the virus takes hold in animal population reservoirs, which would make it hard to eliminate or control in new territories.

Four-fifths of the confirmed monkeypox cases in this epidemic are in Europe and the United Kingdom, but there is also some indication that the number of new monkeypox cases in Europe may be flatlining. It is not clear whether the limited vaccination that has occurred in France and the United Kingdom has contributed to slowing the epidemic. The United States is more of a black box. It currently has 173 confirmed monkeypox cases, but U.S. testing has been very limited so far. Many of the current U.S. cases are not known contacts of one another, which suggests other unidentified cases were the source of those infections.

Others are rightly uncomfortable with a strategy that devotes scarce vaccines and global attention to monkeypox only once the virus has spread to wealthy nations. Monkeypox has long been endemic in Africa. With limited testing, no one knows how many cases there are in endemic countries or whether a change in the virus circulating in those countries has contributed to its global spread. In 2022, deaths have been limited to West Africa and central Africa, where more than 70 people have died from the disease this year. Some experts have argued there is a moral obligation to ensure MVA-BN doses go to Africa as the late-stage clinical trials for MVA-BN were conducted in countries in the region where monkeypox is endemic.

Ahmed Ogwell Ouma, acting director of the Africa Centres for Disease Control and Prevention, has argued that “the place to start any vaccination should be Africa and not elsewhere.” According to press reports, U.S. officials have been noncommittal to date; earlier this month, a senior Biden administration official told The Associated Press that the White House was “exploring all options.” In the meantime, the potential fallout over monkeypox vaccines may threaten nascent efforts to rebuild global cooperation around future pandemic preparedness and response after the stark inequities of the response to the COVID-19 pandemic.


In responding to monkeypox, leaders and experts must recognize that this new outbreak is taking place in the geopolitical shadow of COVID-19. Two and a half years into the pandemic, 82 percent of people in low-income countries have yet to receive even one dose of a COVID-19 vaccine, whereas residents of wealthy countries have abundant access to third and even fourth shots. Promised vaccine donations were, generally speaking, slow to materialize and doled out according to national strategies rather than according to global health needs. The frustrations, unfulfilled promises, and inequity of the COVID-19 response will color how countries cooperate and respond to monkeypox.

At the same time, monkeypox is a different disease than COVID-19, and vaccine allocation should reflect the public health needs of this epidemic rather than attempt to compensate for the shortcomings of the last pandemic response. To tackle the public health priorities of the present crisis while being mindful of the scars remaining from the last one, the world needs a clearly articulated global strategy that makes it clear that African countries, especially those where the disease is endemic, will receive the same priority as wealthy nations, and that is tailored to the particulars of the monkeypox outbreak, the affected populations, and the available medical interventions.

MVA-BN may be a crucial tool in this fight. The vaccine is potentially useful for health workers in all affected countries, including those in Africa in which monkeypox is endemic, because it offers greater protection for those who treat confirmed or suspected patients. Countries with doses should donate a portion of them to WHO global vaccination efforts focusing on health workers.

The frustrations and inequity of the COVID-19 response will color how countries cooperate on monkeypox.

Whether MVA-BN can be effective for a larger containment strategy is not yet clear. The WHO and the governments of affected countries urgently need to conduct more research to determine whether one dose of MVA-BN is sufficient to stop the spread from infected patients to their close contacts. If it is, then vaccines are likely to be most useful in countries where there is adequate surveillance to identify cases and their contacts early and where there is an opportunity to prevent the virus from spreading and becoming endemic. In the near term, that may mean using more doses in Europe and North America, where the outbreak may yet be controlled, and in countries that have the capacity to perform contact tracing.

But such a strategy can only succeed if the WHO, the United States, and other global health donors make equal investments in a robust test-and-treat strategy in settings where limited surveillance stymies contact tracing and weaker health-care systems increase the risk of poor outcomes. Research funders such as BARDA must make investments in improving treatments quickly—and be mindful of the need to develop new antiviral treatments (or treatment combinations) to prevent the emergence of resistant strains of the virus.

Wealthy countries, especially the United States, must avoid re-creating the vaccine nationalism that produced inequity and marred the global response to COVID-19. Failing to do so risks exacerbating the economic, political, social, and health effects of this latest epidemic and threatens to undermine U.S. efforts to rally the world around American leadership in global health.

The monkeypox outbreak may be occurring in the shadow of COVID-19, but the course of the response need not stay within the shadows. By articulating and advancing a clear, need-based public health strategy, countries can avoid a second round of vaccine nationalism and ensure that limited doses go where they can do the most good.

Correction Appended (June 2022)

An earlier version of this article incorrectly stated the name of the vaccine authorized for use against monkeypox. The vaccine is known as MVA-BN, not MVA.

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