How Vaccines Changed the World
Getting a vaccine from development to approval can be a rigorous and time-consuming process, with most estimates putting that timeline at about ten years. The COVID-19 vaccines, which saw fast-tracked production in an active public health emergency, were a notable exception. The record fastest time pre-COVID for the whole process was four years. There are efforts to reduce that time down to one hundred days for future health emergencies, according to CFR Director for Global Health Thomas J. Bollyky.
What Was ‘Operation Warp Speed’?
When COVID-19 began tearing across the world in spring 2020, there were no vaccines to protect against the virus.
To help accelerate the process, the U.S. government launched Operation Warp Speed in May 2020. It was a novel program to figure out how, “instead of taking eight to twelve years to get a vaccine, you could do it in seven months,” then Secretary of Health and Human Services (HHS) Alex Azar said. The program was a public–private partnership that supported multiple vaccine developers based on preliminary evidence of success and good practices. It took interagency coordination between the Centers for Disease Control and Prevention (CDC), FDA, National Institutes of Health, HHS, and Departments of Agriculture and Defense, among others.
The United States first began administering COVID vaccines in December 2020 to high-risk communities, and the first approved vaccine for wide public use came in August 2021. Since then, researchers say millions of infections, hospitalizations, and deaths have been avoided in vaccination campaigns.
The operation achieved successful vaccines in record time in two ways. On the development side, it used mRNA, a molecule involved in protein synthesis, as a delivery mechanism allowing the vaccine to turbocharge through testing. The other was on the regulatory side: regulatory authorities were able to quickly authorize it for emergency use. The WHO granted twelve of the vaccines emergency use listing to spur distribution as safely as possible to end lockdowns.
The makers of the mRNA technology won a Nobel Prize in 2023 for their “unprecedented rate of vaccine development during one of the greatest threats to human health in modern times.” Many scientists believe that mRNA is the best line of defense the world has against future pandemics.
How Have Other Vaccines Been Effective?
Major health authorities including the WHO and CDC have promoted vaccination as the safest way to protect from illness, and much safer than getting sick. Vaccines have saved at least 150 million infants’ and children’s lives in the past fifty years alone in low- and middle-income countries, researchers at the University of Oxford’s data publisher Our World In Data estimate.
The data tells the story of vaccine efficacy on several diseases:
HPV. Human papillomavirus (HPV), a disease linked to cervical and other cancers, is one of the leading causes of cancer in women. The vaccine has been shown to cut cases by around 90 percent where it’s been implemented.
Rotavirus. A diarrheal disease, rotavirus can be deadly among young children. The vaccine has led to up to 70 percent fewer hospitalizations for children under five years old in African countries.
Polio. After the polio vaccine was rolled out in 1955, cases were nearly entirely stamped out. Combined with the WHO-led Global Polio Eradication Initiative that focused on eliminating the disease by 2000, basic immunization programs have been supported worldwide to bring levels down to near eradication.
Measles. Before the vaccine became available in 1963, most children contracted the disease by fifteen years old, leading to around fifty thousand hospitalizations each year. Due to vaccination efforts, the United States was able to declare measles eradicated in 2000. However, outbreaks have begun to crop up again, with the first major case detected in Texas in February 2025. In April 2025, the United States recorded its second death of an unvaccinated child after cases had spread to more than twenty states. By July, CDC data showed more measles cases in the first six months of the year than any year in the last three decades.
What Are the Challenges in Vaccination Efforts?
Factors complicating vaccination include:
Availability of supply. If a government is unprepared for a disease outbreak, it can take a long time, often at least ten years, to either create a vaccine or produce and administer the amount needed for the population.
Equity of procurement is another supply concern. Historically, less-developed countries in the so-called Global South have been the lowest on the list to get vaccines since major vaccine development centers tend to be clustered in wealthier, more developed countries. The resulting effect breeds resentment, political tensions, and distrust—a phenomenon that WHO Director-General Tedros Adhanom Ghebreyesus has called “vaccine apartheid,” referring to the COVID-19 pandemic.
Administration. Lack of access to care is one of the top constraints. The sheer logistics of getting to clinics, such as those in remote, rural areas, and setting up appointments, are a huge barrier, says CFR Senior Fellow for Global Health Prashant Yadav. If vaccine supply happens to run out the day someone visits a clinic, which is not uncommon, he says, some studies show that “50 percent [of people] don’t come back.”
Areas facing violence often are unable to provide medical services, and new disease outbreaks can occur as humanitarian conditions worsen. For example, Gaza has experienced a resurgence in polio, and Sudan has seen cholera outbreaks and HIV prevalence tick up.
Demand. A rise in the number of people— nearly double that of 2021 according to recent opinion surveys of U.S. adults—who either are against vaccines or are wary of them has caused issues in protecting populations against disease.
Why Is Vaccine Skepticism on the Rise?
A wave of global hesitancy about vaccines has bubbled up in recent years, owing to a few root causes.
Vaccine withdrawals have raised concerns among the public. Two studies that linked vaccinations with developing autism published more than twenty years ago have been popular arguments among antivaxxers as well. However, many studies have since debunked this correlation, concluding that the two studies were critically flawed. A swine flu vaccine in 1976 similarly faced severe backlash when it was linked to an increased risk of a serious neurological disorder called Guillain-Barré Syndrome. The U.S. vaccination program was abruptly terminated. “The events dented confidence in public health for years to come,” the BBC wrote in 2020 on the incident.
The rising tide of trepidation stems from many factors, but many experts say it is largely driven by mounting misinformation. It is true that there is a small percentage of the population that has adverse reactions to vaccines, but such instances have become exaggerated. The inaccurate information often comes from social media posts sensationalizing or spreading conspiracy theories and disinformation online, but it can even come from political leaders and foreign actors, such as Russia seeking to sow distrust in the U.S. government. (Several of President Donald Trump’s leading health officials, including RFK, have been vocal critics of vaccines.) CFR’s Yadav says a lack of effective public health messaging has allowed misinformation to thrive.
But the hesitation to get vaccinated has consequences beyond individual health: it harms the greater population, experts say. The WHO has labeled vaccine hesitancy as one of the top ten threats to global health. Vaccination rates have dipped below herd immunity for some highly communicable diseases, even in places like the United States, where the disease has been less challenging to eradicate.
Outbreaks of vaccine-preventable diseases have been rising worldwide since 2020. Concerns about the rapid production of the COVID vaccines and politicization of the U.S. government’s response measures led to significant hesitation from some who opt not to get the vaccine. That has since spilled over into other diseases in years following, health experts believe, as diseases previously almost nonexistent such as measles are on the rise again.
How Can Countries Contribute to Global Vaccination Goals?
Wealthy countries can channel more into supporting other countries when diseases arise, aid experts have said. In one recent example, the United States, Canada, the EU, and others stepped in early to funnel vaccines to several countries to help counter the mpox surge in 2024. Sending vaccines to countries in need is only the first step, experts say. Allocating funds to distribute them is the next one, thus ensuring that once delivered, they actually wind up in pharmacies and on clinic shelves. Yadav sees drones as one promising solution; pilot programs in countries including Ghana and Rwanda have been shown to work.
Other important solutions to these issues include wealthy countries helping lower-income regions produce their own vaccines and build out their health infrastructure. The African Vaccine Manufacturing Accelerator, for example, is a five-year initiative supported by Gavi, a global vaccine alliance organization, to ensure African countries can make more vaccines locally. The African Union has set a goal to manufacture 60 percent of vaccines locally by 2040.
Messaging is another crucial fight, experts, including Yadav, say. “Some combination of health expert advice and social network-relevant advice is what changes the lack of information, and to some degree, the misinformation piece,” he says. Brazil is another example of a country that has made concerted efforts to debunk vaccine rumors, launching a vaccine education movement that has improved vaccination rates.
Is the United States Shifting Away from Being a Vaccine Leader?
The United States has historically been the biggest donor toward global health initiatives, including vaccination programs. In 2024, the U.S. budget for global health was $12 billion, which is only 0.1 percent of the entire U.S. government budget.
This progress could be at risk, health experts say. On his first day in office, Trump withdrew the United States from the WHO, which could result in the WHO losing nearly a fifth of its funding. The body has already shut down at least 83 percent of programs—many of which provided vital health support—housed under the U.S. Agency for International Development. “Without a strong partnership with WHO, some of this effort in advanced science doesn’t translate as quickly,” Yadav says. The WHO could become less inclined to endorse U.S.-made vaccines, and other countries could be less likely to trust them. Trump also put an end to any U.S. funding for Gavi, which vaccinates roughly 70 million children every year.
Pulling the plug on funding health efforts abroad hurts the United States as well. “Better infectious disease management systems abroad make it less likely that terrifying infectious diseases, like Ebola, will become a problem at home,” CFR Africa expert Michelle Gavin writes.
Internally, Trump has put forward some known anti-vaccine advocates to lead his cabinet, including RFK. So far, the Trump administration has largely turned away from vaccine support, coming under scrutiny for downplaying the measles outbreak and inflating the vaccine’s harms, staying markedly quiet on the growing avian flu cases, and defunding programs geared toward making vaccines more effective and widespread. Trump’s 2025 raft of tariffs against other countries—which includes pharmaceutical levies—is also likely to constrain the supply chain of medicine in the United States, several experts have noted.
RFK, for his part, has made a slew of moves to hollow out existing vaccine programs. He hired a discredited vaccine skeptic in March to oversee a review of any ties between vaccinations and autism, a long-debunked claim. Days earlier, the longtime top vaccine official in the FDA resigned over what he called Kennedy’s “misinformation and lies.”
By May, RFK made further waves by revoking the COVID-19 vaccine recommendation for pregnant women and children and dissolving a $600 million contract with Moderna to develop an avian flu vaccine. A month later, he then made the unprecedented move to dismiss all seventeen members of the CDC vaccine advisory committee, accusing the panel of being “plagued with conflicts of interest.” In August, he canceled $500 million in grant contracts for mRNA development. The FDA did approve the updated COVID vaccine later that month, but limited its availability to only the elderly or those with underlying conditions. That same day, CDC Director Susan Monarez was fired only one month into the role after she refused to resign over pressure from RFK to change the vaccine policy. Her legal team, in response to the announcement, retorted that RFK was “weaponizing public health for political gain” and “putting millions of lives of Americans at risk.”
Recommended Resources
This CFR timeline looks at major pandemics of the modern era.
The WHO looks back on the first vaccinations and how far the world has come since then.
Our World in Data does a deep dive into immunization around the world.
The Kaiser Family Foundation charts out what to know about U.S. aid toward global health in ten graphics.
A team of experts covers how to protect a global pandemic treaty from disinformation for Think Global Health.
In their book When the World Closed Its Doors, CFR expert Edward Alden and Western Washington University’s Laurie Trautman explain how the COVID lockdowns forever changed geopolitical and social dynamics.
For Think Global Health, Anya Hirschfeld hands HHS a report card on the progress of the “Make America Healthy Again” agenda.
Mariel Ferragamo is Writer/Editor at CFR. This article is published courtesy of the Council on Foreign Relations (CFR).
