A delayed flu season in North Texas

It's common knowledge in the medical community that viruses like the flu mutate and adapt to maneuver around the latest immunizations. In fact, that's the reason we have to get flu shots every year - because the strains of the flu we were immunized against in prior years have evolved and require us to develop new vaccines for them.

But even as ingenious as mutation is, it may not be as tricky as what the flu did over the past several months in North Texas. You see, the typical peak of the flu season is in January and February here. But not this year. North Texas had an extremely mild amount of flu cases in the first couple of months of 2012.

That lulled most of us into thinking that we were just going to have a flu-less year. However, as you'll learn from our infectious disease expert Dr. Jeffrey Kahn in the WFAA news clip below, the flu just faked us out. There has been a significant increase in flu cases over the last several weeks, which implies that we're just now entering the throes of "flu season."

So, if you haven't had your child vaccinated against the flu yet, it's still a good idea.

Flu questions and myths cleared up

It's been an unseasonably warm winter, and with January and February days in the 60's and 70's, flowers are blooming early and grass hasn't completely gone dormant. The warm winter has also kept flu season from hitting North Texas, but the experts assure us the virus is still sure to hit. It's not an issue of if the flu will hit, but when.

Dallas County Health & Human Services and Children's Medical Center's Infectious Diseases experts both report that there has been a very low incidence of the flu virus in the DFW region so far this winter. But the latest numbers from the County suggest that the virus is ramping up and ready to do its seasonal damage. So, are you protected? The easiest, and safest way to keep you and your family protected from the flu this season, even this late into the winter, is to get a flu shot. And it's not too late, says our Infectious Diseases expert, Dr. Jeffrey Kahn.

Dr. Kahn answered some questions we had in our office about the flu and clears up some of the myths about the flu, like if you can get the flu from a flu shot or not.

Q: What time of year is flu typically at its peak? And why?

Dr. Kahn: Influenza, or the “flu,” typically circulates in the late fall and winter months in the northern hemisphere. During most years, the flu season can last up to 3 months with peak activity lasting 1-2 weeks or more. There is some variability in the start of the flu season—some years it starts in November, while in others (like this one) it can start in February or later. The seasonality of the flu remains one of the great mysteries in infectious diseases. Several potential explanations have been proposed (air temperature, humidity, etc) but none have been proven.

Q: Does wet hair actually make you more likely to catch a cold/the flu?

Dr. Kahn: That’s what our mothers and grandmothers tell us and I am not going to argue with them. So dry your hair and wear a hat!

Q: Can you get the flu by being out in cold weather? And… why is there a flu season?

Dr. Kahn: The flu is typically spread from person to person (so temperature and weather may not have a direct impact) and as we learned with the swine (H1N1) flu, cold weather is not required. The peak of H1N1 activity in Dallas in 2009 was early September when the daily temperatures were in the 80’s and 90’s!

Q: Why do kids’ fevers tend to spike at night? Why do their stuffy noses and coughs seem to get worse at night?

Dr. Kahn: While these are common observations, there is no single answer to these questions. Increase in cough and congestion at night may be the result of position effecting nasal drainage (upright vs. lying down). As for fevers being worse at night, I am not sure that there is solid evidence for this but we know that body temperature varies with the circadian rhythm.

Q: How can you tell the difference between a cold, the flu or some other respiratory virus?

Dr. Kahn: Typically, the flu has a sudden onset with high fevers and body aches. However, it is difficult at times to tell the difference between infection with influenza and infection with other respiratory viruses. But, if it is in the middle of flu season and you suddenly get sick with high temperatures and feel like you’ve been hit by a bus, it’s most likely the flu.

Q: Does Tamiflu really work?

Dr. Kahn: Absolutely! For maximum effect, it should be taken within 48 hours of the onset of symptoms.

Q: Does getting a flu shot give you the flu virus? Will you get sick from the flu shot or flu mist?

Dr. Kahn: The injectable flu vaccine is inactivated (killed) virus so you can’t get the flu from the shot. Flumist is a weakened form of the virus that can only replicate in the nose and does not result in flu symptoms in the VAST majority of recipients. Bottom line: either flu vaccine is SAFE and EFFECTIVE.

Q: Is it too late to get a flu shot?

Dr. Kahn: Since we are just beginning to see flu activity in north Texas, there is still time to get vaccinated. So if you have not already done so, GET THE VACCINE! It’s the best way to protect yourself and your loved ones from getting the flu.