() With the current government shutdown expected to last at least through Friday, health services will be pared back to essential functions.

Critical services, including food inspections and responses to public health emergencies, will continue throughout the duration of a shutdown.

Nearly half of the employees at the Department of Health and Human Services are expected to be furloughed, though some could be called back in the event of a natural disaster or public health emergency.

Here’s how health agencies and services will be impacted:

Centers for Disease Control and Prevention

The agency will continue to respond to “urgent disease outbreaks” and support certain programs, including the vaccines for children program.

Other activities will be stopped, including providing guidance on programs meant to prevent opioid use and the spread of HIV, public communication of health information and analysis of disease surveillance data.

National Institutes of Health

At the NIH, services to provide care and safety for patients will continue, as will any operations needed to secure experiments and care for NIH animals and to protect the security of facilities.

No new patients will be admitted, and some NIH veterinary services will be unavailable.

NIH will also stop holding scientific meetings and grant reviews, and research will be stopped.

Food and Drug Administration

Activities related to threats to human safety will continue, including responding to outbreaks, issuing recalls, responding to public health emergencies and mitigating drug shortages.

User fee funds will be used to continue activities related to regulation, including some activities related to the regulation of drugs and tobacco.

Applications for new drugs, generics, biologics, biosimilars and medical devices will be halted. So will applications for animal drugs. The agency will also stop conducting pre-market safety analysis of novel animal food ingredients for livestock.

Centers for Medicare and Medicaid

Medicaid and Medicare will continue to operate, with payments continuing to be made to providers so patients can get care. Eligibility determination for applications will also continue.

Policymaking activity and surveys of health care facilities are among the activities that will stop during a shutdown.

Food Safety and Inspection Service

Housed under the Department of Agriculture, the FSIS will furlough roughly 500 of its more than 7,600 employees.

Required inspections of food will continue, as will laboratory work related to public health threats.

Administrative work and training for new inspectors will be halted during the shutdown.