Vaccines are healthcare’s first line of defense. From polio to pertussis, rubella to rotavirus, vaccination has saved more lives than any other medical advance in recent history. Vaccines are one of the safest and most cost-effective tools available today – in the United States and around the world – to safeguard our health.

These were some of the points driven home yesterday on Capitol Hill by the Sabin Vaccine Institute’s President of Global Immunization, Bruce Gellin, during a congressional briefing on the importance and safety of vaccines. Dr. Gellin assumed his current role at Sabin earlier this spring after 15 years at the U.S. Department of Health and Human Services, where he was responsible for developing the National Vaccine Plan, among his other duties. He was joined on the briefing’s panel by Nancy Messonnier, director for the National Center for Immunization and Respiratory Diseases at the U.S. Centers for Disease Control and Prevention (CDC), and Paul Offit, pediatrician and director of the Vaccine Education Center at the Children’s Hospital of Philadelphia. The event, sponsored by the American Society of Microbiology, brought together experts from the U.S. government, nongovernmental organizations, industry and research to brief congressional staff on a range domestic and global vaccine and immunization policy issues to inform their work.

Today, global immunization coverage is at its highest-ever level. This progress is thanks in large part to global initiatives, such as Gavi, the Vaccine Alliance, to boost immunization rates in poor countries where access to lifesaving vaccines was historically limited and delayed. Dr. Gellin cited that 580 million children have been immunized and more than 8 million future deaths have been averted since Gavi’s launch in 2000, with the most notable improvement seen in lowest-income countries.

But significant challenges remain in the effort to maximize the global good of vaccines and vaccination. Continued U.S. government support and expertise is vital to future success. As the world has seen most recently in outbreaks of Zika and Ebola, emerging diseases pose significant threats to health and prosperity in every corner of the world. Dr. Messonnier reminded attendees that emerging diseases aren’t the only concern; reemerging diseases, such as measles, pose their own set of health risks.

“Nowadays, measles is rare and parents really don’t understand the risk that they’re taking,” said Dr. Messonnier, alluding to parents who may not follow the vaccination guidelines laid out in the recommended routine childhood immunization schedule. While measles might not be an endemic threat to most American communities, global travel means that an individual can come into contact with an infectious disease abroad and quickly bring it back to their families and communities, triggering an outbreak among unvaccinated individuals at home. Dr. Gellin highlighted such concerns raised in advance of the 2006 FIFA World Cup in Germany, where there was an outbreak of measles at the time of the soccer tournament. “Lots of people were coming into the region, measles was all over Europe, and if you were susceptible then you were going to go home with it.” As a result, attendees were advised to ensure they were vaccinated prior to traveling to the tournament – a measure that is credited with helping to limit the disease’s spread.

Vaccines and vaccination play a critical role in preventing such outbreaks, particularly if the U.S. government and the global health community proactively invest in vaccine development before the next epidemic strikes and the immunization programs that will be responsible for delivering vaccines to communities. Strengthening the everyday immunization programs will ensure that they are able to respond efficiently and effectively in a public health emergency.

Dr. Offit used the story of the rotavirus vaccine to highlight the rigor of the vaccine development process and to demonstrate the impact vaccines can have. Rotavirus is a highly contagious diarrheal disease that can lead to severe dehydration, which can be especially dangerous for young children. Before a rotavirus vaccine was introduced, “rotavirus was ubiquitous,” said Dr. Offit. “It was very hard to find anyone in this country who wasn’t exposed to the virus before the age of five.” From the 1980s until the early 2000s, Dr. Offit and his team worked to develop a safe and effective rotavirus vaccine to help reduce the burden of rotavirus on lives around the world. His efforts paid off, with the United States introducing his rotavirus vaccine in 2006. As of 2012, there was a 94 percent reduction in domestic rotavirus hospitalizations.

In addition to clearly reducing the global burden of many diseases, vaccines across the board have earned a reputation as one of the best buys in global health. A recent study found that for every $1 invested in immunization, there is a $16 return on investment from savings on healthcare costs, lost wages and productivity. With potential return on investment clear, Dr. Gellin emphasized that now is the time to double down on efforts to maximize the impact of vaccines and vaccination.

Part of maximizing the impact includes getting ahead of the curve by investing in vaccine development before the next outbreak strikes. Such an outbreak could be caused by a relative unknown, much like the world saw with Zika or Ebola, but Dr. Messonnier warned of a disease much more common and much more dangerous: influenza.

“If you ask senior scientists, like the former director of the CDC and [NIH’s infectious disease chief] Dr. Anthony Fauci, what they’re scared most of, it’s pandemic influenza,” said Dr. Messonnier. Given its infectiousness and respiratory spread, a new and highly pathogenic strain to which the population is susceptible can spread efficiently from person-to-person, arrive with little warning, and have a global impact and very high mortality rates. When the next pandemic influenza strain emerges, said Dr. Messonnier, the infrastructure and skilled health workers in place will be one of the most valuable safety nets we have to protect ourselves.

Dr. Gellin also spoke to the importance of preparation, highlighting the newly formed Coalition for Epidemic Preparedness Innovations (CEPI) as one initiative working to advance the development of safe, effective and affordable vaccines for epidemic threats. Established in January 2017 with an initial investment of $460 million from private, public and philanthropic organizations, CEPI aims to stop future epidemics by developing new vaccines for emerging infectious diseases. These efforts, combined with ongoing work to ensure that existing vaccines are accessible, are two of the most significant pieces to ensuring that society maximizes the benefit of vaccines and vaccination.

From vaccine development to introduction, the United States has extensive infrastructure in place to ensure that no vaccine reaches the pubic unless it has met the highest standards of safety, quality and effectiveness. In addition to the many part of the U.S. government who keep an eye on vaccine safety, there are currently several federal advisory committees with oversight of the vaccine safety system to ensure that the vaccines we use meet the highest standards of effectiveness and safety. But to ensure that the systems the United States has built and those it has helped internationally, the current challenge is to ensure that current success doesn’t turn into complacency. Securing stable funding to continue these efforts and ensuring that parents fully understand the importance of vaccinating their children against infectious diseases is needed to ensure that our communities are protected from serious infectious diseases that were once common, but are effectively prevented with modern vaccines and a robust public health infrastructure. The U.S. government and health care providers everywhere must do their part to ensure that the children and families whom they care for remain protected from the vaccine-preventable diseases that once threatened so many lives.