What’s behind the dip in coronavirus cases? We ask specialists

After a dramatic post-holiday surge in COVID-19 infections, Massachusetts seems to have found something of a reprieve: Throughout most of January, daily case counts fell steadily, marking the longest period of transmission decline since late spring.

But the drop in cases, however welcome, does not necessarily mean the worst is behind us, disease experts said. And it is unclear precisely why cases are dropping, though more cautious behavior and state-imposed restrictions on restaurants and other gathering spaces could be playing a role.

The scientists also warned that much remains in flux — emerging coronavirus variants, a halting vaccine rollout, people’s continued exhaustion with and resistance to pandemic rules, and redoubled efforts at reopening workplaces and schools. Any of these, they said, could undermine the progress the state and country have seen in recent weeks.

“It’s fabulous that it is [declining],” said Dr. Ashish Jha, dean of the Brown University School of Public Health. “What’s interesting is, it’s happening across the country so it’s not so easy to point to one state’s policies [as the cause].”

Massachusetts has seen a 59 percent decrease in its seven-day average case count, to 2,543.4 on Sunday, down from an all-time high of 6,242.3 on Jan. 8. The United States as a whole also saw a drop-off over that period, with average daily cases falling nearly 40 percent.