Rapid vaccine development does indeed give some cause for optimism. Some counters that I'd have to that would be a potential resurgence of polio in the US [1] a

Rapid vaccine development does indeed give some cause for optimism. Some counters that I'd have to that would be a potential resurgence of polio in the US [1] and the appearance of drug-resistant pathogens (typhoid fever in this case) [2], just to keep us on our toes and curb our enthusiasm... [1] https://www.cdc.gov/mmwr/volumes/71/wr/mm7133e2.htm https://www.cdc.gov/mmwr/volumes/71/wr/mm7133e2.htm [2] https://wwwnc.cdc.gov/travel/notices/watch/xdr-typhoid-fever-pakistan https://wwwnc.cdc.gov/travel/notices/watch/xdr-typhoid-fever...