The public health risk remains low, but bird flu variants have proven to be unpredictable, which is why the virus is a top priority for the federal government.

Moderna has been awarded approximately $590 million from the federal government to help speed up the development of an mRNA-based bird flu vaccine, alongside other influenza vaccines, health officials announced Friday.

CDC officials say medical professionals are seeing more patients whose illness cannot be traced back to an infected animal or bird.

The advisory is intended to prevent delays in identifying human cases of avian influenza A (H5N1) viruses amid high levels of seasonal influenza

The U.S. Centers for Disease Control and Prevention is urging health care workers to accelerate bird flu testing for patients hospitalized with flu symptoms.

The CDC recommends that hospitalized flu patients be tested for bird flu within 24 hours to timely identify avian influenza A (H5N1) cases. While the public risk remains low, faster detection aids in tracing infections and providing swift medical response.

The U.S. Centers for Disease Control and Prevention (CDC) confirmed another human H5N1 avian flu case -- otherwise known as bird flu -- in California on Thursday, bringing the nationwide total of cases to 67.

A child ill with fever and conjunctivitis in San Francisco tested positive for bird flu but had no known source of transmission.

The CDC announced on Thursday its recommendation to test hospitalized influenza A patients more quickly and thoroughly to distinguish between seasonal flu and bird flu.

NBC News Medical Contributor Dr. Kavita Patel speaks with Gadi Schwartz about the difference in symptoms between a cold and the flu and explains the CDC's urge for faster testing to find human bird flu cases.