With flu season already hitting hard in parts of the world and COVID-19 still going around, public health experts are sounding the alarm that this could be a rough season for respiratory illnesses.

The colder months typically bring a rise in sicknesses like the flu and COVID. But this year, doctors are trying to respond without the usual data from the Centers for Disease Control and Prevention, which stopped being released when the government shutdown began at the start of October.

“As an infectious disease specialist, I look to the CDC for guidance in terms of early signals that there’s something going on in my area of practice,” said Dr. Linda Nabha.

With the shutdown, many CDC staff members who monitor the spread of the illnesses have been furloughed. Nabha said the information they gather and release is essential to tracking outbreaks, underscoring that without it, doctors are — in a way — flying blind.

“If the surveillance is weaker, then we may have less up-to-date information … and it may be harder for public health officials to detect early signals of a bad flu season or emerging strains,” Nabha said.

She said local and state health departments may try to fill the gap, but it’s a tough ask for local agencies.

“We’re essentially asking a certain number of employees to make up for the work of a bigger surveillance group,” she said.

Nabha said the flu is already hitting hard overseas, which could be a warning sign.

“It raises the risk that we may see hospitalizations and more severe disease, and we may see it earlier,” she said.

She urged people not to wait to get vaccinated, and said better planning is needed for any future government shutdowns.

“We do have to think about what the next season is going to bring if we don’t have those numbers right now,” Nabha said.