DMV flu cases: Here’s how weather affects the flu

DMV flu cases: Here’s how weather affects the flu

WASHINGTON – Flu activity is low in the DMV, but is slowly starting to increase in DC. The Centers for Disease Control and Prevention (CDC) shows that activity in D.C. is considered moderate.

The CDC uses an influenza-like illness scale, which consists of minimal, low, moderate, high, and very high.

In Maryland cases are minimal. The Maryland Department of Health reported one influenza-related death in 2023.

In Virginia, cases are low. While in West Virginia, influenza activity is minimal.

Across the United States, Puerto Rico is showing high flu activity, followed by Alaska, which is also showing high activity. D.C., New Mexico, Louisiana, Mississippi, Georgia, and Florida are all showing moderate influenza activity.

The rest of the country fits in with minimal or low activity.

RELATED: Here’s how to stay flu-free over the Thanksgiving holiday

As temperatures drop, flu cases are likely to rise. The researchers found that temperature and humidity play a role in transmission.

The CDC noted that influenza viruses can be detected throughout the year. For the United States, seasonal influenza activity often begins in October or November and peaks between December and February.

So what is the winter connection? The influenza virus appears to be immunized at cold temperatures, according to research by the National Institutes of Health (NIH).


It’s as if the cold has given the virus a protective layer. The outer membrane of the influenza virus is composed of lipids that include lipids, oils, waxes, and cholesterol. These fats do not mix well with water. The researchers found that the lipid covering hardens and turns into a gelatinous substance at temperatures slightly above or below 32 degrees.

Researchers believe that the gel-shaped outer coating helps the virus survive at cooler temperatures and spread from person to person. Once in the respiratory tract, the body’s warmth causes the covering to melt, allowing the virus to infect a person’s cells.

At 70 degrees, the lipid envelope remains in gel form. At a temperature above 70 degrees, the gel begins to melt into a liquid phase. Researchers believe that the liquid phase does not protect the virus from the elements, causing the virus to lose some of its ability to spread in warm air. National Institutes of Health experts point out that as the weather warms, influenza viruses dry out and weaken.

This has been observed in relation to influenza in America. It should be noted that in tropical climates, influenza also spreads in places that are usually warm and humid.


Running a humidifier in the winter not only combats dry air, but it can also help avoid getting the flu. Influenza is not a fan of moisture. The virus works best in dry air. When humidity increases, the virus loses its ability to be infectious, a study in PLOS ONE noted. This study noted coughing as a way to spread the virus. With the relative humidity set at 45%, the researchers noted that 52% of the virus lost its infectivity, or the ability of the pathogen to cause infection.

Low humidity may affect our bodies’ ability to defend ourselves against the flu. A study in the National Academy of Sciences found that exposure to dry air may impair the mucociliary clearance function. Science Direct defines MMC function as “a critical, physiologically regulated protective function of the airways and lungs that is essential for the clearance of respiratory pathogens.”

It loses some of its ability to remove pathogens, the researchers said.

Yes, you can use a hygrometer to help monitor the humidity levels in your home, but it depends on the relative humidity, which is temperature-dependent.

Other contributors

Sunlight and vitamin D
During the winter months we may not be exposed to as much sunlight which in turn may limit our ability to produce vitamin D.

A study published by the National Institutes of Health found that low levels of vitamin D were associated with colds and flu. Although the study is not conclusive, it indicated that 24% of people with low levels of vitamin D experienced upper respiratory infections compared to 17% of participants with higher levels of vitamin D.

The gathering is near
Some experts at Harvard also believe that the way people’s habits change in winter could also be a contributing factor. For example, people spend more time indoors and are more likely to breathe the same air as infected people. People infected with the influenza virus can spread it to others within up to six feet.

Climate change and influenza

Researchers are trying to determine how climate change will affect influenza. One study conducted at the US National Library of Medicine of the National Institutes of Health found that milder winters are usually followed by an earlier, more severe flu season the following winter.

The study published in 2013 indicated, “We hypothesize that warm winters are more likely to be followed by earlier, more severe influenza seasons because the number of people infected is reduced by warm weather, leaving an abnormally large fraction of susceptible individuals in the population in the following season. Next season will likely be exacerbated by the early onset “If the onset occurs before most of the population has had the opportunity to be vaccinated.”

Download the new WUSA9 app here.

Sign up for the Get Up DC newsletter: Your expectations. Your commute. your news.

You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *