Just like police on a stakeout, epidemiologists for the state and local health departments monitor influenza-like illness (ILI) on many fronts: Emergency Room visits for flu-like illnesses reported, school absenteeism is monitored and certain clinics submit samples from every patient with ILI. Monitoring begins nationally in October and continues through May.
In San Antonio, the first cases are typically seen in November and peak in January and February, with only a few cases identified after early March.
So when my Blackberry buzzed in April 2009 with a message from our flu surveillance team that an “untypable strain” of flu had been found in two teenagers from Guadalupe County, we hoped it was an isolated infection. At the time, I was the communicable disease program manager for the Texas Department of State Health Services Region 8. It was the end of the season and we knew it could be a glitch in testing – or it could be the start of something significant.
It wasn’t long before we knew this was no typical flu. Initial tests showed a similarity to swine flu. Swine flu circulates in pigs, not people, yet the patients had not been in contact with pigs. The reasonable assumption was that they acquired it from another person. This would mean the swine flu virus had mutated. After years of planning for the possibility that avian flu would mutate, the appearance of different animal flu virus infecting humans sent shock waves through the public health community.
In a typical flu season, those at risk for serious complications tend to be the very young or very old: 60 percent of the hospitalizations and 90 percent of flu deaths are in people over 65. What became the Pandemic of 2009 didn’t appear to be as severe as the Spanish Flu Pandemic of 1918.
The 2009 strain, H1N1, produced a relatively mild illness in many people, but when it did attack severely, it attacked the young, healthy, and often, pregnant women.
Of the 12,470 deaths attributed to H1N1 in the U.S. that year, 78 percent occurred in persons between the ages of 18 and 64. Ninety percent of the hospitalizations for H1N1 were in people under 65.
This is the exact opposite of what occurs in any “usual” flu season. Six percent of H1N1 flu deaths were in pregnant women.
Why does this history lesson matter now?
The major strain circulating this year in Texas is the pandemic strain, H1N1. As of Jan. 17, about 97 percent of the confirmed flu cases in Texas subtyped were identified as H1N1. The other 3 percent were H3N2.
Developing a flu vaccine is a bit of a guessing game. Because it takes many months to develop a flu vaccine, each year scientists predict which strains will be circulating the following season based on a number of factors. The good news is that the scientists were right this year. Included in the 2013-2014 flu vaccine is H1N1, H3N2, and two Flu B strains.
The bad news is that by the third week of January, like in 2009, otherwise healthy adults between the ages of 20 and 55 are falling victim to H1N1. There have been at least two deaths in Texas children due to H1N1 and many hospitalizations. Nine adults, all under 65 and all unvaccinated, have died from the flu in Texas. Because reporting of deaths due to flu in adults is not required in Texas, the real number could be higher.
Chief Epidemiologist Dr. Anil Mangla of the San Antonio Metro Health District says that while the total number of flu cases appears to be similar to last year, the severity of the disease in the younger population is similar to 2009.
So what can you do to protect yourself and those around you? Always, wash hands with soap and water, cough in your arm instead of your hand, stay home when you’re sick (don’t try to be a martyr at work), keep your sick kids home from school. Eat well and exercise, keep your body otherwise healthy. And get a flu shot. As Dr. Jason Bowling, Hospital Epidemiologist at UHS says, “The flu shot is one tool in your arsenal against influenza.”
You May Say:
“I got the shot once and got sick.”
The flu shot contains a *killed* virus. This means there’s no live virus there to make you sick. You will probably get a sore arm, and for a very few people, a headache. Severe adverse reactions are extremely rare. So why did you get sick? It takes 1-4 days after exposure to influenza to show symptoms. It takes about two weeks after getting the vaccine to develop protective immunity. You may have already been infected before you got the vaccine.
Or you may not have had the flu at all. There are many flu-like illnesses circulating during flu season. Only 30% of the ILI patients tested in Texas have had influenza, others tested positive for rhinoviruses (the common cold), RSV, and HPMV (human metapneumovirus).
Some years, the scientists are off in their prediction, and the influenza virus circulating is different from those strains included in the vaccine, making it less effective. This year, the prediction has been spot on. The 2013-2014 vaccine protects against the influenza strains circulating so now.
“I heard protection doesn’t last for long.”
All studies indicate protection lasts for 6-8 months at least, the duration of the flu season. You have to get a new vaccine every year because the virus strains circulating are different. The influenza virus can change its surface molecules so the immune system’s memory doesn’t recognize it. Dr. Santanu Bose, Associate Professor of Immunology and Microbiology at UTHSCSA explained, “The virus is like a student, learning the host’s defense mechanisms and changing to evade them. We don’t know how the virus is evolving, we have no control over it.” What we can do, is predict how it might evolve. Most years we can predict it accurately. Sometimes, a novel virus subtype emerges, as it did in 2009.
“If I got the H1N1 shot in 2009, do I need another shot?”
Yes. Dr. Bowling explained that immunity produced by the vaccine appears to wane over time. It’s not clear how long protection lasts beyond the 6-8 month window. So consider this a type of booster shot.
“Is the shot better than the nasal spray?”
Both vaccines contain the same virus subtypes. You’re getting the same vaccine either way. The difference is that the nasal spray contains a “live attenuated virus.” This means that the virus is not killed as it is in the shot, but it is significantly altered so that it doesn’t make you ill but still induces immunity. Because of that, it’s not recommended for children under 2 or adults older than 49, pregnant women or people who are immunocompromised
So why get the nasal spray instead of the shot? It appears to produce a more effective and longer lasting immunity in kids. And kids usually prefer a spray over a needle.
“Who should not get vaccinated?”
Infants less than six months old are too young to be vaccinated, all the more reason why caregivers and everyone around that infant should protect themselves.
People who have an allergy to eggs, because the vaccine is made in unfertilized chicken eggs, could have an adverse reaction. However, a variant has been made which was grown without eggs, so ask your doctor if this is available. There were four vaccines made this year.
“Where do I get a shot?”
See your health care provider first if you have any concerns.H-E-B, Walmart, and Target pharmacies offer for them for people seven years old and older. Texas Med Clinics offer them to kids as young as four years old. San Antonio Metro Health Clinics also offer them. Due to high demand they’ve occasionally run out, but have been able to restock quickly. Call first to make sure they have them in stock. Click on each provider above for a link to their services or visit the Texas Department of State Health Services’ website for a flu shot locator at www.dshs.state.tx.us.
I’ve had flu at least three times in my adult life, the last being over New Year’s Eve 2004, when I didn’t get a shot. Seven days in bed, barely able to eat or move. I never, ever, want to have it again. I’m sure you don’t want to do that either.
Cherise Rohr-Allegrini, PhD, MPH, teaches microbiology at the University of the Incarnate Word. After studying malaria in Thailand, she was the Pandemic Flu coordinator and epidemiologist for the San Antonio Metro Health Department and later the Communicable Disease Program Manager with the Department of State Health Services, Region 8. She also serves as the Science Chair for Bonham Academy’s PTA. She can be contacted at email@example.com.