Healthcare workers begin receiving their second dose of COVID-19 vaccine at MercyHealth in Janesville.

According to a news release, health care workers in Rock County who got their first dose in December will receive their second dose from a new allotment of Pfizer vaccine starting this week.

Pfizer reports its vaccine is 95 percent effective in preventing COVID-19 among people who had no evidence of prior infection. Due to limited allocation, and based on federal and state guidance, the first shipments of the Pfizer vaccine were given to category 1A health care workers.