across the country. reporter: early fda analysis showing moderna s vaccine is nearly 95% effective and appears to prevent severe disease. preliminary evidence also suggests the vaccine reduced asymptomatic infection in volunteers by two-thirds after the first shot. temporary side effects include fever, headache and fatigue. neil browning was one of the first to get two doses of the moderna vaccine in a trial back in march. i ve been enrolled now for almost nine months. i ve had no symptoms other than the sore arm after each morning. reporter: for now, the pfizer vaccine rollout in full swing. the push to vaccinate this country expected to expand next week to 1,100 nursing homes. in the next wave, first responders, teachers and food workers, followed by people over the age of 65 and those with pre-existing conditions. hackensack hospital in new jersey has treated more people with covid than any other hospital in the state and the patients keep coming.