MISSION, Kan. (AP) — The COVID-19 surge is stretching oxygen supplies tight and sending hospitals scrambling for more ventilators, even as there are glimmers of hope in some hotspots.

In Tulsa, Oklahoma, a hospital recently called 911 after coming within just a few hours of running out of oxygen because they needed an emergency transfer for a patient on high-flow oxygen.

But there are signs of optimism in some parts of the country. Cases and hospitalizations are dropping in some of the worst-off states.

LOOK: Answers to 30 common COVID-19 vaccine questions

While much is still unknown about the coronavirus and the future, what is known is that the currently available vaccines have gone through all three trial phases and are safe and effective. It will be necessary for as many Americans as possible to be vaccinated in order to finally return to some level of pre-pandemic normalcy, and hopefully these 30 answers provided here will help readers get vaccinated as soon they are able.