Archive for September, 2010

Study shows flu vaccine prevents heart attacks

Tuesday, September 28th, 2010

A new study just published in the Canadian Medical Association Journal concluded that influenza immunization reduces the risk of heart attack (acute myocardial infarction) by 19% in people over the age of 40. The study covered seven flu seasons, from 2001 to 2007, and included 78,706 patients living in England and Wales, a huge population that was possible to study because of the national healthcare system database in the United Kingdom.

The main conclusion is not very surprising; other studies have shown similar effects. Influenza attacks the lungs and makes your heart work much harder to pump your blood through the congested tissue. If you are going to have a heart attack, it is more likely you will have it when your lungs are damaged from influenza. Conversely, protection from lung infection would remove this risk factor for heart attack. This is why people with cardiac diaease have always been considered a high-risk group that should get their flu shots every year.

In digging deeper into the results, you discover that the authors found a few other facts that I think are important but the popular press will probably miss. The study found that timing was important. People who got their immunization early in the season (from September to mid-November) were more protected from heart attacks (21% versus 12%) than people who got their vaccine later (from mid-November on). Flu is always around before the official flu season starts, and it seems like it is better to be protected early than to wait until the epidemic starts.

Another little fact reported by the authors was that you were not protected against heart attack if you were immunized the previous year but not the current year. Only the current vaccine protected you for the current flu season. You had to be immunized every year to be protected.

The authors did not extend the study to a financial analysis, but it seems clear to me that preventing a very expensive thing like a heart attack makes the flu shot even more cost effective.

This large population-based study reinforces things that we have been saying about influenza prevention: flu shots are cost-effective and cost-avoiding, get immunized every year, and get immunized early.

Givving flu shots to hospitalized patients

Friday, September 24th, 2010

Bronson Methodist Hospital is begining a program this week to offer influenza immunizations to patients in the hospital. Bronson has done this for many years and it has become a standard policy for most hospitals in the US. Some agencies that look at the quality of medical care even grade hospitals on how successfully they immunize inpatients.

Immunizing hospital patients during the influenza season is a brilliant idea for several reasons. Patients in the hospital typically have time for it so they don’t have to make an extra appointment and drive somewhere to get their immunization. Nurses typically give patients many other drugs for their primary disease, so one more is not much extra work. Patients who are in the hospital are typically sick with some other disease like heart or lung problems, and they are at high risk for influenza already. And including the cost of the vaccine in a hospital stay avoids the work of submitting another bill to your insurance. Studies show that immunizing hospital patients during the influenza season prevents readmission for influenza later and saves a lot of money.

Hospitals typically give only the intramuscular shots to inpatients because the intranasal mist vaccine is not approved by the FDA for patients who are sick.

Some people still question whether you should give a vaccine to a person who is in the hospital for another disease or condition. Other than treatments to suppress a patient’s immune system, no diseases or treatments make a patient inelligible for or interfere with the response of a patient to a vaccine. You can give a patient with pneumonia a flu shot. The shot will not harm the patient and the vaccine will work pefectly well in that patient after they recover and go home.

If you or someone you know is going into a hospital for any reason between September and April and you have not had your flu shot yet, go ahead and let your nurse give you one while you are there.

When is the best time to get my flu immunization?

Wednesday, September 15th, 2010

I am frequently asked about the best time to get an influenza immunization. Often it is asked in the form of other questions like “isn’t it too early,” “will it last all season,” “should I wait until October,” or “will the protection wear off?” Some doctors were taught, and tell their patients, that if you get immunized early (in August or September), protection will not last the whole season. All these questions suggest that people think that vaccines are like other drugs that are excreted or eliminated from the body and the drug and its effects go away after days, weeks or months.

Vaccines are not like antibiotics or other drugs. They change the body’s immune system forever. Their effects never go away completely. The immune system remembers every vaccine we ever received since we were children. Certainly the immune system does not stay as aroused or activated as it was right after we get an infection or take a vaccine, but the immune memory of that encounter stays with us forever, and if we encounter that disease again the immune system will respond strongly.

The immune memory after a flu immunization lasts the whole season, so there is no advantage in waiting to take the vaccine. It does not expire after a certain date like a gift card. The best time to get an influenza immunization is whenever you can. If that is in August, go ahead. If it is March or April and you still haven’t been immunized and there is still influenza around, go ahead; it is also never too late to get immunized.

Having said that, there is a kernel of truth to the idea of limited protection of influenza vaccines. The problem is that the virus is constantly changing by genetic mutation. If the virus changes a lot during the season, the vaccine may not protect you against the virus as well later in the year as early in the year, but that is not because the vaccine or your immune system failed, and taking the old vaccine later would not have protected you against the newly mutated vaccine. If that happens, the virus outsmarted us, and there is nothing we could have done about it.

The best thing to do is to get immunized as soon as you can; then you have done everything you can do to protect yourself whenever the flu season starts.