Dr. Eric Yager, associate professor of microbiology and chair of the Department of Allied Health Sciences at ACPHS, teaches classes in immunology and virology. We asked him to share his expertise with all of us at a time when we're looking to stay immune to common viruses that can make people sick.
Why do certain infections peak during the colder months?
Infections by respiratory viruses like influenza, RSV, COVID-19 and cold viruses tend to peak between December and February for several reasons.
First, colder temperatures and lower humidity allow viruses to survive longer outside the body. The longer they survive, the greater chance they have to infect a person. Related, lower humidity and dry air can reduce the amount of mucus lining our respiratory tracts. Mucus normally works as a first line of defense to trap and disarm airborne microbes. Reduced mucus results in increased vulnerability to infection by airborne viruses.
Second, increased amount of travel surrounding the holidays allows respiratory viruses to spread more quickly from one community to another.
Third, people tend to spend more time indoors where there is less ventilation and air circulation compared to being outdoors, which allows viruses to pass more readily from one person to another.
How can someone distinguish between common illnesses like the flu, a cold, or COVID-19, and when should they seek medical care?
The flu, RSV, COVID-19 and common cold have many similar symptoms – cough, fever, headache, sneezing, runny nose and congestion. The best way to determine which virus you are infected with is to get tested.
For most individuals, respiratory virus infections are mild and resolve over time with rest and self-care. Individuals should seek medical care, however, if they have trouble breathing, shortness of breath, chest pain, severe weakness or muscle pain, a high fever that doesn’t go away or extreme nausea. In addition, certain individuals are known to be at increased risk for serious disease and hospitalization if infected with these viruses: infants, older adults, pregnant people, those with weakened immune systems and those with chronic diseases like asthma, diabetes, heart disease, kidney disease and liver disease.
What are the most effective habits people can adopt to reduce their risk of getting sick during cold and flu season?
One of the most effective ways to reduce your risk of getting sick is to get vaccinated. The U.S. Centers for Disease Control and Prevention recommends getting your flu vaccine before winter, but if the flu is circulating in your community, it’s not too late to get your shot.
Regarding RSV, a vaccine is now available for adults aged 60 and older and for pregnant people. Injectable monoclonal antibodies that can help prevent severe RSV in infants and young children are also available. This is good news because in the United States, RSV causes as many as 80,000 hospitalizations in children under 5 years old and more than 100,000 hospitalizations in older adults.
Lastly, the COVID-19 vaccine has been updated to protect against the current circulating strains of virus. It’s important that individuals at risk for severe disease stay up to date with their COVID-19 vaccine.
In addition to vaccines, practicing good hand hygiene, avoiding close contact with people you know are sick and staying hydrated can all help reduce the risk of getting sick during cold and flu season. Studies support that regular exercise, eating a balanced diet rich in whole foods and getting enough sleep (seven to nine hours each night) can also help keep your immune system healthy and reduce your risk of getting sick throughout the year.
How do vaccinations protect against seasonal illnesses? Are they foolproof?
Safe and effective vaccines are available for flu, RSV and COVID-19. They train your immune system to recognize and defend against these viruses without your experiencing a full-blown infection. The protection takes time to develop (a couple of weeks) and may require more than one dose. However, once vaccine protection reaches maximal levels, this protection is durable, lasting throughout the cold and flu season if not longer. Certain vaccines, such as those to prevent from flu and COVID-19, need to be updated periodically to protect against new strains of viruses that emerge.
No vaccine provides complete, 100% protection from infection; vaccinated individuals can still get sick. However, vaccinated individuals are much more likely to experience milder symptoms and are at a reduced risk for severe complications and hospitalization following infection compared to unvaccinated individuals.
In addition, being vaccinated can help reduce community spread of seasonal viruses. If enough individuals are vaccinated against a disease, the virus can’t travel as easily from person to person. This means that even individuals in the community unable to get vaccinated will benefit from some protection against getting sick.
What precautions should people take to protect others if they start feeling sick, especially in crowded or shared spaces?
General precautions people should take if they start to feel ill include staying home from school or work (if possible) to prevent the spread of infection to others. Similarly, limit your contact with individuals who are at an increased risk for serious disease and hospitalization. Covering your mouth and nose when coughing or sneezing is another way to prevent those around you from getting sick. Wearing a mask is an additional strategy.
The CDC website is an excellent resource for timely, data-driven, science-based recommendations on how people can protect themselves and others from flu, RSV and COVID-19.