Peak flu season, norovirus, and H5N1 avian flu

Key takeaways:

• Respiratory round up
• Norovirus
• Avian flu 

Respiratory virus roundup

Influenza (flu) is dominating respiratory viral illness both nationally and locally, with 38% of tested samples in the past week at Yale Health positive for flu, compared with 7% for RSV and 4% for COVID. In Connecticut, flu is driving emergency department (ED) visits and hospitalization for respiratory illness, especially among children aged 0-4 years old. 

Vaccines

The Yale Flu and COVID Vaccine Program ends on January 31. Vaccines are still available through the Yale Health Immunization Department for Yale Health members and students (self-schedule through MyChart) or through your healthcare provider.

• The COVID vaccine is still likely to be beneficial if you have not yet had this season’s vaccine. 
  • Early data suggests that the current COVID vaccine effectively reduces hospitalizations and urgent care visits.
  • Those aged 65 or older or immunocompromised should get a second dose of the COVID vaccine 6 months after the first dose.
• The flu vaccine is recommended as long as the virus continues to circulate.

What should you be doing now?

• Keep masks handy and use them in crowds, healthcare settings, around vulnerable people, or any time you’d like an extra layer of protection against circulating viruses.
• Stay home from work or class if you are ill. You may return to activities when your fever is gone for at least 24 hours and your symptoms are clearly improving; however, please continue to wear a mask for five days.
• Testing for flu and COVID can be helpful, especially if you are at increased risk of severe illness and a candidate for treatment.
  • A negative rapid antigen test soon after symptoms begin does NOT rule out infection and should be repeated in 48 hours.
  • Combined flu and COVID home test kits are available at pharmacies and at Yale Health at reduced cost.

Who should seek care?

In most cases, you can and should ride out your illness at home. Exceptions include:

• Those with severe symptoms such as persistent fever, shortness of breath;
• Anyone at increased risk — such as immunocompromised people, very young children, older adults, or their household members;
• Candidates for treatment for flu or COVID.

Norovirus

Norovirus outbreaks are at a historic high, both nationally and in our region. Risks are higher in communal settings with shared bathrooms and food service, like dorms. The extremely contagious virus is spread by contact with contaminated surfaces or personal items or through sharing food or drink with an infected person. While the campus is not currently in an outbreak situation, our custodial staff and hospitality teams are taking extra precautions, and we hope you will too. Key actions include:

• Washing hands with soap and water after using the toilet (alcohol-based hand sanitizers do not work against norovirus).
• Cleaning high-touch surfaces with a bleach-based cleaner.
• Staying home if ill and for at least 48 hours before returning to work or class.

H5N1 avian influenza

Avian influenza (a.k.a. bird flu) has continued to spread among millions of livestock animals, wild birds, and other mammals around the country. And now it has arrived in Connecticut. This month, for the first time in this outbreak, H5N1 was detected in a backyard flock (ducks, geese, and peacocks) in Connecticut. The flock has been euthanized. A second detection in a backyard flock in New Haven County was recently reported.

Avian influenza is also known to infect and cause severe disease or death in cats. Infection has resulted after cats drank raw milk, ate food containing raw animal products, or contacted dead poultry or wild birds.

More disease in animals increases the risk that the virus could change genetically in ways that increase the risk to humans.

Human cases. To date, the CDC has reported 67 confirmed and 7 probable cases in humans, with one fatality in Louisiana. With a few exceptions, these patients had documented contact with infected animals, and most experienced mild illness. 

Despite the ongoing outbreak in animals and cases in humans, the CDC rates the risk to the general public as low. What would raise that risk?

• Evidence of person-to-person spread. This key indicator of increasing risk of epidemic potential has NOT been seen yet.
• More human cases without clear evidence of exposure to infected animals.
• Evidence of genetic changes that would allow it to more easily spread to and among humans. The virus would need to mutate to preferentially interact with a receptor in the human upper airway. Those genetic changes have not yet been detected. 

What is being done to reduce risk? 

• Efforts to limit the outbreak in animals. This has proved challenging and requires coordination among the livestock industry, states, and the federal government.
• Efforts to limit occupational risk for people who work with animals through education and personal protective equipment.
• Surveillance for evidence of further spread, including testing for H5N1 among hospitalized influenza A cases and agricultural workers, in raw milk, and in wastewater.
• Vaccine development, laboratory test development, and evolving guidance for clinicians.

What should you be doing now?

• Those with backyard flocks should take precautions, watch for sick birds, and notify the state Department of Agriculture if concerns arise.
• Hunters, agricultural workers, and others should avoid handling dead birds.
• Don’t feed your pets food containing raw animal products and keep them from eating dead birds. The American Veterinary Medical Association has information regarding pets and backyard flocks.

As a nation and a community, we have plenty of ways to interrupt the spread of viruses, even ones as challenging as HSN1, especially when we work together. Campus Health is dedicated to keeping the Yale community informed, aware, and prepared for public health challenges.

In health,

Madeline S. Wilson, MD, FACP
Chief Campus Health Officer