The rapid spread of medical rumors and false or misleading information on social media during times of uncertainty is a vexing challenge that threatens public health. Understanding the information ecosystem, social media networks, and the scope of incentives that drive users and social media platforms can provide critical insights for strong coordination between stakeholders and funders to address this challenge. The COVID-19 pandemic created an opportunity to demonstrate the role of media monitoring and counter-messaging efforts in responding to dangerous medical rumors, misinformation, and disinformation. It also highlighted the challenges. The efforts of ThisIsOurShot and VacunateYa to spread accurate health information about COVID-19 and COVID-19 vaccines are described and lessons learned are discussed. These lessons include the need for substantial financial investments at the local and national levels to sustain and scale these types of programs. Examples in other fields that offer a path forward include Information Sharing and Analysis Centers and Public Health Emergency Operations Centers. Understanding the scale and scope of what it takes to address viral medical rumors, misinformation, and disinformation in a networked information environment should inspire elected leaders to consider policy and regulatory reforms. Our transformed information ecosystem requires new public health infrastructure to address information that threatens personal safety and population health.