DOCTORS CORNER

The Upcoming Influenza Season

By Michael Wall MD, OHSU CF Center Director

The upcoming influenza season promises to be more concerning and confusing than usual so I thought I would provide some background, dispel some myths, and urge everyone to take some personal control of their situation.

1. Let’s talk about the “regular” or seasonal influenza that comes around every year. Seasonal influenza comes in 2 major types: A and B. Every year we have an epidemic of at least one of these types and sometimes both. The epidemics usually start in about December and last through perhaps April. Influenza typically starts with fever, muscle aches, and cold symptoms. People are contagious from a day or two before they start having symptoms until they are on the mend and their fever is gone. There are lots of other viruses that come around the community at the same time as influenza and typically we hear people say “I have the flu” when they may or may not really have influenza.

2. Both Influenza A and B viruses have an ability to mutate or change from year to year. That is the reason the immunity from flu shots is only good for about a year. Each year our government, other countries, and various international health agencies determine which influenza strain(s) should be included in that year’s vaccine. How do they do this? Well, influenza typically spreads from Asia or Australia to the U.S. The various agencies that are involved try to determine what strains of influenza are most likely to cause the next year’s epidemic by keeping a close eye on the situation overseas. They try to predict which strains will cause problems many months prior to the start of the flu season in order to give companies enough lead time to produce vaccine. The fact of the matter is that most of the time they hit their predictions correctly but not all the time. That is the reason that some years the vaccine is more effective than others. In addition people should be aware that no vaccine is 100% effective and some people may get the flu even if they have had their immunization.

3. As of the present time the flu vaccine is mostly administered in a shot (as opposed to nasal spray). The influenza viruses that are used to make up the vaccine are killed before the vaccine is made. Thus, to dispel one myth, people do not get the flu directly from the shot. However, the immune response mounted by the body to the vaccine can certainly cause a couple of days of low grade fever and some muscle aches. The viral strains used to make the vaccine are grown in chicken eggs so people with major egg allergy should not receive the vaccine.

4. In terms of therapy once a person already has the flu there is a drug that can help with Influenza type A. That drug is Tamiflu and it is useful in preventing the infection from becoming really severe in some people with underlying disease (such as CF). There is no specific drug therapy widely in use for influenza type B. So how do we know when or if to start Tamiflu in a person with a chronic, underlying health problem like CF? Well, IF we know that the predominant influenza strain in the community is type A, and IF the patient calls us as soon as they start having symptoms we may start Tamiflu.

5. Who should receive the seasonal vaccine? Below are the federal recommendations. Basically everyone with CF from 6 months of age on up should receive the vaccine. Since the vaccine is not always 100% effective other members of the household may want to get vaccinated as well.

• Children aged 6 months up to their 19th birthday

• Pregnant women
• People 50 years of age and older
• People of any age with certain chronic medical conditions
• People who live in nursing homes and other long-term care facilities
• People who live with or care for those at high risk for complications from flu, including:
  • Health care workers
  • Household contacts of persons at high risk for complications from the flu
  • Household contacts and out of home caregivers of children less than 6 months of age (these children are too young to be vaccinated)

6. OK, now what about the swine flu? The swine flu strain is an influenza type A also known as H1N1. In some respects it is little different than the usual seasonal flu. The symptoms are the same. Despite all the publicity it is not really a much “worse” strain of influenza than seasonal flu. The fact is that each year about 40,000 people in the U.S. die from complications of seasonal flu and so far the death rates from H1N1 are about the same. The main problem with H1N1 is that it is more spreadable than seasonal flu and it has not followed the classic seasonal pattern. It did go down a bit this summer but is predicted to back in force this fall.

7. Swine flu vaccination. As everyone knows there has been a major push to develop a swine flu vaccine and first doses will be available soon. It now appears we will only need one shot and not two for protection. Below are the current recommendations for the swine flu vaccine. Note that these recommendations are pretty similar to those for the seasonal flu vaccine and would certainly include everyone with CF.

The groups recommended to receive the 2009 H1N1 influenza vaccine so far include:

• Pregnant women because they are at higher risk of complications and can potentially provide protection to infants who cannot be vaccinated;
• Household contacts and caregivers for children younger than 6 months of age because younger infants are at higher risk of influenza-related complications and cannot be vaccinated. Vaccination of those in close contact with infants younger than 6 months old might help protect infants by “cocooning” them from the virus;
• Healthcare and emergency medical services personnel because infections among healthcare workers have been reported and this can be a potential source of infection for vulnerable patients. Also, increased absenteeism in this population could reduce healthcare system capacity;
• All people from 6 months through 24 years of age
  • Children from 6 months through 18 years of age because cases of 2009 H1N1 influenza have been seen in children who are in close contact with each other in school and day care settings, which increases the likelihood of disease spread, and
  • Young adults 19 through 24 years of age because many cases of 2009 H1N1 influenza have been seen in these healthy young adults and they often live, work, and study in close proximity, and they are a frequently mobile population; and,
• Persons aged 25 through 64 years who have health conditions associated with higher risk of medical complications from influenza.

8. The bottom line is that everyone with CF should get a seasonal and a swine flu vaccine. In addition people in the household who are in any of the above groups should be vaccinated. The shots can be given together or separated by a few weeks.

9. Planning for and getting the vaccines. Now is the time for all of you to be planning when and how to receive your vaccinations. For many of you the best approach will be to contact your local doctor and/or county health department. Tell them you have a child with CF (or CF yourself) and you really need to receive the vaccinations asap. Find out their plans for vaccine distribution and stay on top of the situation locally so you can arrange for vaccination as it becomes available. We all know there will be some shortage of swine flu vaccine initially so it will be really important to have a plan in place before the rush begins. OHSU will have some doses of vaccine available but because many of you live at a distance and because our supplies for patients will be limited I would urge you to get prepared to receive your vaccinations locally if at all possible.