US health officials remain on high alert for one unfinished task of the fight against coronavirus- the unvaccinated people who could be a breeding ground for new variants of coronavirus. There is the danger that a new mutation of the virus in unvaccinated people could be more resistant to vaccines. This means everyone needs to get vaccinated, and one dose should be followed quickly with the second dose. One dose only has limited protection with strong level of antibodies resulting only after the second dose. In the US southern states such as Arkansas and Oklahoma lag behind in vaccination, and are seeing a large increase in cases.