There are two types of influenza (flu) that cause disease in humans, Influenza A and B, and there are an untold number of other viruses that cause “influenza-like illness” (ILI) in humans.
Flu and flu vaccine(s)
There are two types of influenza (flu) that cause disease in humans, Influenza A and B, and there are an untold number of other viruses that cause “influenza-like illness” (ILI) in humans. Influenza is important because anyone who comes down with it feels very bad for several days, and it can lead to death in some people. Most people who die of flu are either elderly or they are young children, and most of these die from a complication such as pneumonia. Getting a flu vaccine will generally reduce the likelihood that an individual will come down with the flu by 40 to 60%. However, the value of immunization extends beyond the individual who is immunized. As we noted last week, the key to eliminating smallpox was the immunization of people in contact with the sick, so it is with flu as a study done here in Texas shows. Focused efforts to increase immunization of school children against flu in Temple/Belton area resulted in a reduction of 8 to 18% of flu cases in adults (35+y/o), even though there was no increase in immunization rates for adults in Temple/Belton. This is compared to the control populations in Waco, Bryan and College Station who did not have the added emphasis on immunization for school children. This highly significant result was achieved, even though only 25% of the children in Temple/Belton were actually immunized. In another project, 85 percent of the school-age children in Tecumseh, Michigan were vaccinated against influenza A (H3N2) just before the epidemic in 1968, resulting in a 67 percent decrease in the attack rate of epidemic flu in that community, compared to a similar nearby community.
Vaccines work by exposing the body to an agent that is like the disease causing agent, but does not cause the disease. This effectively “teaches” the body to respond effectively when it is exposed to the actual disease causing agent. The way that this teaching occurs seems almost miraculous, in that every person is born with an immune system that is capable of attacking literally millions of different germs (viruses, bacteria, fungi), by first identifying the germ, and then mounting various defenses aimed specifically at that germ. The way that the body identifies a germ is as if each germ has one or more keys (antigens), and when one of these keys fits into a lock in the body’s immune system the body unleashes the appropriate targeted defense. It takes about two weeks for the defense to achieve maximum effectiveness, but once it has been unleashed the body stands ready and waiting for another assault by any germ that has the same key. That is why we try to immunize people two or more weeks before the expected exposure.
There are now several different vaccines for the flu. Although there are intranasal vaccines the most effective vaccines are shots, and these are safe for virtually everyone, even those who have egg allergies or are pregnant. All flu vaccines this year are effective against the same three strains – two types of A (H1N1 and H3N2) and one type of influenza B. Some manufacturers add a second strain of B antigen. The reason that flu vaccines are not more effective that 40-60% is that there are hundreds of strains of flu that differ in their antigens. In 2009 there was a small pandemic associated with the “Bird Flu”, a type of Influenza A. Even though the 2009 vaccine contained H1N1 antigen, the new strain was sufficiently different so as to render the vaccine ineffective against it. This new H1N1 has replaced the old H1N1 in the environment, and the 2017 vaccine is effective against it.
The CDC advises everyone who is older than 6 months should get a flu shot, preferably by the end of October. I agree, and I received mine on October 12.
Dr. Bundrant is the chief of staff at Ballinger Memorial Hospital. He is a member of the Health and Wellness Coalition of Runnels County which is comprised of health care professionals throughout the county. Members meet on the first Thursday of the first full week of the month.