Influenza occurs in the winter. Florida’s weird winters makes predicting the upcoming influenza season complex. Analysis of the 2018-2019 US CDC data reveals a DOUBLE PEAK influenza season. The early outbreaks were related to the Influenza Type A, strain H1N1. The later peak was caused by the Influenza Type A strain H3N2. We can get a glimpse into the possible upcoming season by watching Australia’s current flu season. Their winter months (and thus their flu outbreaks) happen in July and August but this year, the flu did something unexpected. Outbreaks started in March with a steady rise and what appears to be a high mortality rate.
We have to watch this up-coming flu season carefully.
This CDC closes the influenza surveillance in week 31 and publishes a final report of the prior years statistics. The 2018-2019 vaccine conveyed an overall protection of 47% against the H1N1 Type strain in adults and a higher level of protection for children between the ages of 6mos and 17 years, which was closer to 67%. There was less protection against the H3N1 Type A strain,; it is this strain that predominantly impacts the elderly. The H3N1 strain of the virus caused a double peaked in late March, stretching the flu season into May. Indeed, our office had a confirmed rapid influenza test in the office in mid-May for Type A influenza..
The rapid nasal swab we perform in the office differentiates Type A from Type B but it does not send viral culture confirmatin to the CDC. This means many actual cases of influenza go unreported until insurance companies assist the government with data collection, which is based on the diagnosis codes we attach to our office visits and billings. That influenza data can take more than a year to compile.
Additionally, there are two (2) subtypes of Influeza B, but it is widely believed that Influenza B is milder than the Type A strains…..or at least that has been the historical pattern. The recent genetic shifts and mutations have occured in the Type A viruses. Virologists worldwide monitor these viral shifts. And these shifts are used to select the strains to be used in the next year’s vaccine production. Due to the double peak in the 2018-2019 flu season, the CDC delayed the strain selection for the new 2019-2020 vaccines until late March. They wanted to monitor the virus’s activities. This year there are two versions of the vaccines in production. All vaccines in this country are produced by private companies and their supply and availability depends on their laboratory production and inspections. The vaccines cannot be released for purchase until they meet criteria.
The signs at Publix have gone up: get your vaccine and get a $10 gift card. The concern is that vaccinating in August for a virus that may have a prolonged and protracted season, may mean a loss of immunity in the spring of 2020. In some years, the outbreaks peak in December. This year, that second H3N1 peaked in late March, meaning flu infectiosn continued for up to six weeks from the peak.
If you have the chance to be vaccinated at school or work, go for it! If you do not have asthma or other immune suppressive conditions, you can take the nasal vaccine which is a live-attentuated influenza vaccine. It is the form of vaccination offered in our public schools. If you are elderly, which is defined as anyone 65 and older, you should get the high dose vaccine.
The high-dose vaccine confers a stronger immunity response to the viruses. There is solid, strong evidence that catching the flu – if you are elderly or infirmed – increases your risk of heart attacks and strokes. The reason is that the viral infections provokes an widespread inflammatory event across all body systems and for those at risk, it can trigger cardiovascular events.
Some very smart and curious investigators made the connection between the admission rates to the hospital for influenza and influenza-induced pneumonias and secondary heart attacks and strokes. While the flu may not cause the death, it increases the risk for the heart attack or stroke that does cause a death.
So the goal as your family doctors: get you vaccinated. We want to see you when you get sick, collect a rapid flu test, treat with anti-virals and quarantine you to contain spread. Wash your hands. Use your sick leave. Keep sick children home. Avoid your elderly family members.
The flu vaccine only works if it is in your arm. It does not work on the shelf.