The world has come a long way since the COVID-19 pandemic began. There are now vaccines, at-home tests, masks and treatments. With all of these tools available, why is COVID still here?Health policy correspondent Selena Simmons-Duffin talks to Scientist-In-Residence Regina Barber about what we can learn from the public health advocates working to end the HIV epidemic, how those lessons may translate to ending COVID and why having the scientific tools isn't enough.