CDC Director Robert Redfield issued a stark warning on Wednesday, saying that if the nation fails to follow guidelines on slowing the spread of COVID — social distancing, mask-wearing, avoiding large gatherings — that this Fall could be the worst on record when the virus hits the flu season. (Get those flu shots people!)

More than 166,000 Americans have now died from COVID-19 and the average number of deaths has remained at just over 1,000 per day for two weeks.

‘For your country right now and for the war that we’re in against covid, I’m asking you to do four simple things: wear a mask, social distance, wash your hands and be smart about crowds,’ Redfield said in an interview with WebMD.

‘I’m not asking some of America to do it. We all gotta do it,’ he added, stressing that the guidelines are only effective if between 95 and 99 percent of people adhere to them.

Asked what he thinks the pandemic will look like by Thanksgiving, Redfield cited the opening line from Charles Dickens’ 1859 novel A Tale of Two Cities.  ‘It’s really the worst of times or the best of times, depending on the American public. I’m optimistic,’ he said.

In an optimist note, Redfield says he is “very cautiously optimistic” about having a vaccine before the end of the year. Six vaccine candidates are “moving forward extremely rapidly,” he said. Three vaccines began phase III clinical trials 2 weeks ago. He expects a fourth to begin the final stage of trials soon. The final results of those trials may be available by the end of October or beginning of November.