The Johnson & Johnson vaccine pause dealt a blow to the U.S. vaccination effort, but given that the vaccine only made up 5 percent of the shots given domestically, experts think it will likely have a much greater impact abroad.
Here are five ways the pause could reverberate worldwide:
Jeopardize the global vaccine effort
Safety warnings about Johnson & Johnson's vaccine and a potential link to a rare but serious type of blood clot could hamper efforts to speed vaccinations in developing countries.
Combined with the vaccine manufactured by AstraZeneca, Johnson & Johnson's single-dose shot is meant to be a major part of the global supply of coronavirus vaccines.
The company is slated to provide up to a billion doses to countries around the world. It's easy to store, without any complicated deep-freeze requirements like the mRNA vaccines made by Pfizer and Moderna, and Johnson & Johnson has pledged to sell the shots at cost, without making a profit.
But so far it has manufactured only a fraction of that amount, and questions about safety are likely to linger amid the supply shortages.
It's also not just the U.S. that decided to pause using the vaccine. Johnson & Johnson said it was pausing its European rollout, and health authorities in South Africa also announced that they were putting it on hold. Australia said it was not going to purchase any doses from J&J even as the nation struggles with its vaccination.
Increase vaccine hesitancy
Most experts said the impact on global supply would be fairly limited if countries resume using the J&J vaccine in the next week or two.
The bigger concern is that a pause of any duration could deal a blow to vaccine confidence.
"The challenge is that anytime there is news of adverse events, that may have an impact on willingness to vaccinate, whether it be specifically with that vaccine, or vaccinate against COVID, more broadly," said Elizabeth Shakhnovich, a consultant with Oliver Wyman's Health & Life Science Practice.
A particular concern is that the decision to pause the use of J&J's shot followed the pauses of another adenovirus-based vaccine, developed by AstraZeneca and Oxford University, in the European Union and many of its member states.
"We watched this story over the last couple of weeks with AstraZeneca," Shakhnovich said. "There was some level of hesitancy around vaccination in general in Europe, and then the stories of adverse side effects emerged," and vindicated the vaccine skeptics.
American officials have taken great pains to say the Johnson & Johnson vaccine is safe, and they recommended the pause only out of an abundance of caution. But reasoning and nuance doesn't always filter through. People's faith in the shot will be undercut, even though it works.
"It ends up being a game of telephone. Unfortunately, six out of seven and a half million patients affected by clotting ... you know, that number doesn't necessarily get passed along correctly," said Vikram Bakhru, chief operating officer at ConsejoSano, a company specializing in health equity.
Slow U.S. recovery
Infectious disease experts have long argued that vaccination is a global effort; the U.S. will not be completely able to get back to normal until the rest of the world is also vaccinated.
"I think we have a responsibility to vaccinate the rest of the world, both from a humanitarian standpoint as well as from a global health security standpoint to ensure that we don't have further variants that threaten both the rest of the world as well as the United States," Centers for Disease Control and Prevention (CDC) Director Rochelle WalenskyRochelle WalenskyNew CDC studies show boosters provide strong protection from omicron variant The Hill's Morning Report - Presented by Facebook - Biden talks, Senate balks The Hill's Morning Report - Presented by Facebook - Voting rights week for Democrats (again) MORE said Friday during a White House briefing.
Even as new infections climb, vaccinations in the U.S. are increasing rapidly, and the nation is on track to get a majority of Americans inoculated in the coming months.
Sectors of the economy that don't rely as heavily on other countries will recover quicker, and life may return to a semblance of normality. Still, experts say continued vigilance will be key, especially with regards to international travel.
Shakhnovich said she expects the U.S. might put travel restrictions on countries with high levels of infection, widespread variants and low vaccination rates.
Even if the CDC recommends resuming using the Johnson & Johnson vaccine, rich countries have already helped to further the perception that it's a second-rate shot by pivoting almost exclusively to mRNA vaccines.
President BidenJoe BidenSunday shows preview: US reaffirms support for Ukraine amid threat of Russian invasion The Fed has a clear mandate to mitigate climate risks Biden says Roe v. Wade under attack like 'never before' MORE said the U.S. has more than enough supply of vaccines from Pfizer-BioNtech and Moderna to make up for any J&J slowdowns. The European Union is reportedly in talks to buy 1.8 billion more doses from Pfizer-BioNTech.
If developing countries feel slighted, and think that rich countries are dumping their rejected vaccines on poorer nations, that could also slow the global vaccine rollout and further the inequities between nations.
Bakhru said countries shouldn't abandon the use of any vaccine that can save lives in a pandemic, and the ones jumping ship based on extremely small numbers of adverse events are doing a disservice to the rest of the world.
"The beauty of time and of administering is that they will prove effective, they will lower rates of disease in these communities, and trust will be built," he said.
Deal a blow to vaccine diplomacy
If developing countries feel slighted by the West, they may look to Russia and China, which have made vaccines readily available.
Russia and China have been using their coronavirus vaccines to gain influence in the world, mainly in Latin America and some Asian nations, even while obscuring the safety and efficacy of those shots.
U.S. officials are focused on ensuring every American is vaccinated before donating excess doses to the rest of the world, which could also create an opening for Russian and Chinese influence.
The U.S. is well aware of the possibility.
Secretary of State Antony BlinkenAntony BlinkenSunday shows preview: US reaffirms support for Ukraine amid threat of Russian invasion Coons opposes sending US troops to Ukraine: 'We would simply be sacrificing them' Overnight Defense & National Security — US, Russia meet during 'critical' point MORE in a recent speech noted that when the time comes for the U.S. to send doses overseas, the nation "won’t trade shots in arms for political favors. This is about saving lives."