When is the best time to get my flu immunization?

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.

A special flu vaccine for seniors

August 20th, 2010

Influenza vaccine works quite well in young adults. On average, it is 70% to 90% protective in that population. The range is quite wide because each influenza season is different, and some years the virus and the vaccine do not match each other as well as in other years.

In people over about the age of 65, however, the vaccine protection starts to drop. As we get older, our immune system does not respond to new challenges as well as when we were young. It still responds; just not as well. Scientists have studied ways to get the immune system of seniors to respond to vaccines better. We have tried giving multiple doses, adding an immune stimulator called an adjuvant to the vaccine, and increasing the dose of the vaccine. A new high-dose flu vaccine for seniors is available this season, and it works.

The high-dose vaccine contains four times more vaccine per dose than the standard vaccine. It is approved by the FDA for people over 65. It is recommended by the CDC, although the standard vaccine is also approved by the FDA and acceptable for this population.

The high dose vaccine was tested in 2575 seniors in a large trial, and it produced significantly better immunity than the standard dose. Because the high-dose vaccine is new and has obviously not been used against the 2010-11 influenza viruses, we will not know how well it will perform this year until the season is over and we can compare the numbers.

I think it is great that we have a vaccine that is tailored to this specific population rather than giving the same vaccine to everyone. The regular vaccine still works, and I still recommend it, but if you are over 65 and can get the high-dose vaccine, I would get it.

WHO: “The H1N1 pandemic is over”

August 16th, 2010

Last week the World Health Organization declared that the H1N1 influenza pandemic was over. The technical term they used to describe the situation is “post-pandemic period.” Interestingly, the US Centers for Disease Control and Prevention (CDC) announced the same week that this year’s flu season had already begun. How can both groups be right, and who should we believe?

They are both right. Let me explain. A pandemic is a statistically-significant increase in the number of cases of a disease worldwide or across more than one continent. The term “post-pandemic” means that the disease has returned to the level normally seen for influenza at that time and place. It doesn’t mean the virus went completely away. H1N1 is still around. It has just receded into the background or normal level of influenza we see every year, so the WHO is right.

Wasn’t the WHO announcement late? Yes, the H1N1 epidemic was probably over in the US several months ago. But remember that the WHO looks at the whole world, not just the US, and they have to wait and watch for a while after a pandemic is over to make sure it is not going to return, so this announcement looks to us in the US like old news.

So why did the CDC just say that flu is back? Summer is usually off-season for influenza in the US and other countries in the Northern hemisphere. The number of cases is low, but it still occurs. It can occur when groups of people get together, like at summer residential and sports camps. There have been clusters of cases reported already this summer, and the strain of flu we are seeing now is not H1N1 from last year, it is a new strain called H3N2.

Is this new H3N2 virus going to cause a pandemic like the H1N1 virus of 2009? No one knows, but I would guess not. Remember that we had no vaccine against H1N1 when it first came out, so the virus got ahead of us. The new H3N2 is covered by this year’s flu vaccine, so when we start immunizing people over the next month, we will be ahead of the virus.

One flu vaccine this year

August 4th, 2010

Last year (2009) was an unusual year for influenza for several reasons. Mostly because we needed two different vaccines. The normal flu vaccine contains three strains of virus and is designed to protect us from all the strains of the virus we are likely to encounter that year. Nature fooled us last year. A new virus strain, type H1N1, emerged and spread around the world after our regular vaccine was already in production. We made a new vaccine just for H1N1 and gave it after we gave the regular vaccine. Results showed that the H1N1 vaccine was a very good one, and probably prevented a lot of death and disease last year.

This year the new H1N1 strain is included in the regular vaccine, so we don’t need two vaccines. One vaccine will do the job. Even if a new strain emerged now, it is too late to make another vaccine this year anyway.

Some may think that if they took the H1N1 vaccine last year, they don’t need this year’s vaccine, but that is not true. The other two strains of flu will be coming back, and we need protection against all three, not just H1N1.

If you are a Bronson patient and want to make an appointment to get your flu immunization, we have an online registration system or call your doctor’s office. Vaccine is arriving at doctor’s offices and clinics in August, so it is not too early to make your appointment.

One flu vaccine next season

February 19th, 2010

The World Health Organization (WHO) recommends the strains to be included in each season’s influenza vaccine. The WHO yesterday (2/18/10) recommended that the pandemic H1N1 strain that caused epidemics in the United States in April and October be included in the 2010/2011 influenza vaccine. The official name of the virus is A/California/7/2009 (H1N1). Influenza viruses are named by the type (A), the location where the strain was first officially identified (California, even though we suspect it originated in Mexico), and the year. This is the same strain that was in the H1N1 vaccine this year.

Because this strain will now be included in all the standard influenza vaccines next season, we will not need a second vaccine for this strain. One vaccine should be all we need, unless some new strain emerges again. It is a challenge to get people immunized each year with one vaccine, and having to give two vaccines to prevent influenza in 2009 was clearly a barrier to protecting the public. One dose will be much easier.

Although the 2009 H1N1 influenza epidemic was severe in certain populations and caused many deaths, the good news is that the vaccine made for it has been very safe and effective, and the virus remains susceptible to our antiviral drugs we use to treat it.

This is National Influenza Vaccination Week

January 11th, 2010

The CDC issued the following press release urging people to get immunized this week.

“The week of January 10-16 marks this flu season’s National Influenza Vaccination Week, a national observance established to highlight the importance of ongoing influenza vaccination beyond the fall. Providers are encouraged to continue vaccinating high risk persons with the seasonal vaccine and to expand 2009 H1N1 vaccination to anyone who wants it, regardless of age. Because supply and availability of the 2009 H1N1 vaccine have increased dramatically, CDC is now encouraging people who have been patiently waiting to receive the 2009 H1N1 vaccine to get vaccinated as well as continuing to encourage unvaccinated people in priority groups to get vaccinated. Activities during the upcoming week will enhance public awareness about ongoing influenza vaccination efforts. Influenza is unpredictable, but influenza is expected to continue for months, caused by either 2009 H1N1 viruses or regular seasonal influenza viruses.”

People sometimes think that there is a point in the influenza season at which it is too late or not worth being immunized. That is not true. The influenza season can be long, lasting until April or longer. We continue to immunize susceptible people until April each year or until our vaccine is gone. Remember that influenza immunizations are cumulative. A vaccine that you take late in the season may not be needed that year, but it may protect you the next year, or ten years from now.

This week’s CDC influenza update says that H1N1 influenza is still showing up all over the US, Europe, and Central and East Asia. Although the rates are lower than their peak in October, the epidemic is sustaining itself, so you can still get H1N1 influenza almost anywhere in the world. If you have not received your H1N1 vaccine yet, you should get it before the manufacturers stop making it and the supply runs out.

A special flu vaccine for the elderly

January 4th, 2010

We have known for many years that people over the age of 60 or 65 do not respond to immunizations as well as younger people. We can measure the response and function of their immune system and look at the failure rate of immunization (people who were immunized and still got influenza) in that population, and by both measures, the effectiveness of immunization declines with age after a certain point.

For years, we just accepted this as a fact that we could not help. The elderly die of influenza; they always did and they always will, right?

Not so fast. The problem with vaccine studies in the elderly is that they use the same vaccine dose in all patients of all ages. An 80 year old gets the same dose as a 10 year old patient. New data show that the elderly will respond adequately to vaccines, but you have to use a higher dose. A vaccine at 2 to 4 times the normal dose will give the same amount of protection to an elderly person as the normal dose to a young person.

A pharmaceutical company finally took advantage of this information and came out with a high-dose influenza vaccine for people 65 and older. It contains exactly the same ingredients as the normal dose, but in four times higher concentration, and it produces the same protection in the elderly as a normal dose does in a young person. The FDA approved this product on December 23, 2009. The product will be made in 2010 and available for the 2010 influenza season.

Every patient is different, and the response of each individual to a vaccine is different. Influenza vaccine does not protect 100% of the people who take it, but this new vaccine should raise the effectiveness of the vaccine in the elderly up to about the same as in the younger population. If a significant number of elderly people take this vaccine next year, it will be interesting to see if it makes a difference.

Looking for something fun to do over vacation?

December 22nd, 2009

With children home from school and people taking time off from work, holidays are a time for families to do things together. How about getting your flu shots? That may not be the first thing that you thought of doing, but think about it.

Vaccine is available, and available to everyone. We first limited the product to certain priority groups, but now the H1N1 vaccine is in good supply, more is being shipped every week, and it should be easy to find a provider where you can get it. Physician offices, county health departments, and some retail pharmacies are providing it now.

You need it. Although most of the priority groups have been covered, children, adults, and the elderly not in priority groups have not been covered until now, so it is your turn. The virus is still circulating in the US, and many more people will still get the flu this year, so now is a good time to protect yourself.

There is no charge for the vaccine. Some providers may charge a small fee to give it, but the vaccine itself is free to the patient. Think of it as insurance or an investment; you are getting future protection against risk.

You have time now. It is hard to take time off from school or work to get an immunization, but during vacation you don’t have to worry about that. Pack up the kids and grandparents and get everyone immunized. That would be a good way to start the new year off right, by improving your health.

Changes in hospital visitation guidelines

December 21st, 2009

Hospitals care for people who are sick and very susceptible to infectious diseases. Visitors to hospitals can carry contagious diseases with them and give them to the patients they visit. All hospitals have visitation guidelines to reduce the risk of infection, and hospitals often adjust their visitation guidelines to respond to local infection risk. Michigan has just had an unusually large outbreak of influenza caused by the new H1N1 strain. We adjusted our visitation guidelines in October to make our hospital as safe as it could be, and now that the first wave of influenza seems to be over, we are returning to our prior guidelines. Here are the new guidelines.

“Effective immediately, limited visitation guidelines implemented during the H1N1 flu season are lifted for Bronson Methodist Hospital (BMH), Bronson LakeView Hospital (BLH) and Bronson Vicksburg Hospital (BVH). These guidelines were put in place to safeguard patients from flu exposure. Since we have seen a steady decline in influenza activity, we feel it is important to lift these restrictions so patients, families and friends may be together. In general, children under age 15 may visit all areas and family and friends outside the immediate family may visit the OB areas. We realize there are times where this may be limited due to the individual patient’s condition and ask you to continue to partner with patients, families and the care team to make this decision. We will continue to monitor our patients’ risk to flu exposure and inform you if it is necessary to limit visitation again.”

The influenza season is not over, and we are likely to have another wave of cases. If it seems prudent to return to the enhanced restrictions again, we will do that. We value the support that loved ones give to our patients, but keeping our patients safe is our primary responsibility, and we hope you understand if we have to limit visitors during epidemics. If you have any questions about this, please make a comment, email the “fludoctor” address, or ask your loved one’s care team about it.

H1N1 vaccine recalled

December 17th, 2009

What does it mean that some of the new H1N1 influenza vaccine was recalled recently? In my opinion, very little. So far, four batches of vaccine from one manufacturer have been recalled. This is a small amount of the total vaccine being made, and it will be replaced by the manufacturer.

The recall was not for a safety issue. It related to the stated potency of the vaccine. The FDA approved this vaccine at a potency of 15 micrograms of influenza protein per 0.5 milliliter dose, or 7.5 micrograms per 25 milliliter dose (half-dose) for babies. That doesn’t mean that a slightly lower dose would not work, it only means that the FDA approved that dose.

One can imagine that the pharmaceutical companies that are making this vaccine want to make as many doses as possible with the vaccine they have, so they are not over-filling the syringes with vaccine. The recalled vaccine met the potency requirements when it was made and shipped, but after it sat in the syringes for a while, a little bit of the vaccine may have stuck to the inside of the syringe, and when it was dispensed, it was slightly below the 7.5 microgram amount. The FDA is taking a hard-line position that the vaccine needs to meet the specifications not just when it leaves the factory, but until it expires, so they recalled it. This just shows how rigorous the FDA is with the new vaccine.

There is normally a large cushion of variation when vaccine dosing is set. Different people respond to different doses. Most people will respond to a lower vaccine dose than the FDA-approved one, so there is no reason to think that the recalled vaccine was not strong enough, and it certainly is safe. If your child received the recalled vaccine, don’t worry about it. If you are a provider and had some of the recalled vaccine in your refrigerator, you should turn in the recalled vaccine and replace it with the fresh product.