Just after Thanksgiving I saw an 11 year old patient who was brought in for fever, cough, and nasal congestion.

 

His mom said that it started with a sore throat about 4 days ago, then he developed a hacky cough and a clear runny nose. The sore throat only lasted 1-2 days, but he had a low grade fever and he was very congested. The cough wasn’t bad but seemed to be worse at night when he laid down and he said his ears were plugged.
 

In the office, his temperature was 99.6, he has red weepy eyes and his throat was red, but not that impressive. He did have significant post with the exception of some mucus that he could cough and clear, there was nothing to suggest a pneumonia. Of note, he said that he was actually feeling better than the day before but he also added that at times, his calves hurt. With that, I asked the nurse to do a swab for the flu. We have a nasal swab in the office that will detect influenza A or B.
 

The swab confirmed my suspicious that he had influenza B.

 

I told mom that it was too late to give him Tamiflu (a medication that can shorten the course and ease the symptoms of flu if started in the first 1-2 days of illness) but we talked about the conservative measure she could use to give him relief. When we were finishing up, he smiled and said, “Well, I guess I don’t need to get a flu shot this year.” His mom then said, “Boy, you lucked out. I was going to bring all my kids in this week for their flu shot.”
 

They were both stunned when I told them that when he was over this illness, he SHOULD get a flu shot to protect him against influenza A.

 

I explained that we were seeing a lot of influenza B in the office and that it was early in the season. The ‘flu season’ starts in the fall and can last until May. It is expected that the typical surge of flu cases would be in late December and January and would be more of a influenza A which we haven’t seen as of yet…but no doubt it is coming.
 

There are four strains of influenza A, B, C, and D. Influenza A occurs in humans, birds, and pigs. Influenza B occurs only in humans and influenza D only occurs in cattle. Influenza A and B are the strains that cause seasonal epidemics in humans and influenza A has been associated with the more serious pandemics. Influenza A accounts for around 75% of all cases of flu and B accounts for the remaining 25%. It is widely held that certain strains of influenza A cause more severe illness but a study in 2015 showed that A and B strains cause similar rates of illness and death.
 

The World Health Organization has over 100 National influenza centers in over 100 countries that conduct surveillance studies and gather data each year about the circulating strains of influenza around the globe.

 

The meet every February and determine which strains of flu they predict will be prevalent during the upcoming flu season and with that data they make their recommendations about which strains should be in the flu shot for that year. In February they make their recommendations for the Southern Hemisphere. In the United States, the FDA has the final say on the strains that are to be in the flu shot is ‘spot on’ and in others it may be marginal.
 

The quadrivalent flu shot for this winter has 4 strains. They include H1N1 A/Brisbane, H3N3 A/Kansas, B/Colorado and B/Phuket. So there are 2 strains for influenza A, and 2 strains for influenza B.

 

My patient had influenza B in late November and he had a relatively mild case and should be well in a short while. But that doesn’t mean that he couldn’t get a more serious case of influenza A when the flu season really hits later this winter. That is why he should still get the flu shot when he gets over this illness to protect him against influenza A…much to his chagrin.