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Health Alert Network (HAN) Reports and Updates

CDC’s Health Alert Network (HAN) is CDC’s primary method of sharing cleared information about urgent public health incidents with public information officers; federal, state, territorial, tribal, and local public health practitioners; clinicians; and public health laboratories.

CDC’s HAN collaborates with federal, state, territorial, tribal, and city/county partners to develop protocols and stakeholder relationships that will ensure a robust interoperable platform for the rapid distribution of public health information.


Categories of Health Alert Network messages:

Health Alert - Requires immediate action or attention; highest level of importance

Health Advisory -  May not require immediate action; provides important information for a specific incident or situation

Health Update - Unlikely to require immediate action; provides updated information regarding an incident or situation

HAN Info Service - Does not require immediate action; provides general public health information


The SARS-CoV-2 Omicron variant has quickly become the dominant variant of concern in the United States and is present in all 50 states. The Centers for Disease Control and Prevention (CDC) recommends that eligible individuals should get all vaccines and booster shots as the best preventive measure available against severe disease, hospitalizations, and death due to COVID-19. Therapeutics are also available for preventing and treating COVID-19 in specific at-risk populations. These therapeutics differ in efficacy, route of administration, risk profile, and whether they are authorized by the U.S Food and Drug Administration (FDA) for adults only or adults and certain pediatric populations. Some therapeutics are in short supply, but availability is expected to increase in the coming months. This Health Alert Network (HAN) Health Advisory serves to familiarize healthcare providers with available therapeutics, understand how and when to prescribe and prioritize them, and recognize contraindications.

Due to the increased transmissibility of the SARS-CoV-2 Omicron variant and concerns about potential impacts on the healthcare system, the Centers for Disease Control and Prevention (CDC) is updating recommendations to enhance protection for healthcare personnel, patients, and visitors, and ensure adequate staffing in healthcare facilities. The guidance is based on the limited information currently available about the Omicron variant and will be updated as needed as new information becomes available.

Omicron, a new SARS-CoV-2 variant, has been identified in many countries and categorized as a Variant of Concern by the U.S. government and the World Health Organization (WHO). Because little is known about Omicron currently, it is important for the public health and medical communities as well as the general public to remain vigilant to reduce potential exposure. This Health Alert Network (HAN) Health Advisory summarizes current knowledge about Omicron and provides recommendations on how to detect the Omicron variant within the United States as soon as possible to mitigate its spread.

The Centers for Disease Control and Prevention (CDC) is issuing this Health Alert Network (HAN) Health Advisory about increased influenza A(H3N2) activity that could mark the beginning of the 2021-2022 influenza season.

The Centers for Disease Control and Prevention (CDC) is issuing this Health Alert Network (HAN) Health Update as an update to HAN Update 454: Expansion of Recall of LeadCare Blood Lead Tests Due to Risk of Falsely Low Results that CDC issued on October 14, 2021. The purpose of this HAN Update is to clarify options for retesting children who were tested with the recalled LeadCare lead test kits. The information in this HAN Update remains the same as HAN Update 454, except for the new information added below in bold in the Recommendations for Clinicians section.