Swine flu is widespread in North America.

The U.S. centers for disease control includes asthmatics in a list of people who might want to consider bringing antiviral medications with them when traveling, according to an October 12 update on the H1N1 (swine) flu epidemic. The CDC recommends that asthmatics should talk with their doctors about what to do if they develop flu symptoms while traveling and whether they should consider taking antivirals with them as a treatment option.

“Together, they should look carefully at the 2009 H1N1 flu situation at their destination and the available health-care options in the area when considering what would be best in their situation,”the CDC advised.

The H1N1 influenza virus is making its way through most countries in the Northern Hemisphere, and its particularly active in North America, according to the World Health Organization. As of October 17, 2009, there were more than 414,000 laboratory-confirmed cases worldwide and nearly 5,000 deaths reported to the WHO. “As many countries have stopped counting individual cases, particularly of milder illness, the case count is significantly lower than the actually number of cases that have occurred,” the WHO wrote in recent flu update.

The CDC reports that visits to doctors for influenza-like illness climbed rapidly during the second week of October, and overall are much higher than what is normally expected for this time of year. Forty-six states are reporting widespread influenza activity and almost all cases identified so far are 2009 H1N1 influenza.

“People with severe asthma often take high doses of glucocorticoids that can suppress their immune system, placing them at greater risk for infection and possibly serious disease caused by 2009 H1N1 influenza virus,” says NIAID Director Anthony S. Fauci, M.D. “We need to determine the optimal dose of 2009 H1N1 influenza vaccine that can be safely administered to this at-risk population and whether one or two doses are needed to produce an immune response that is predictive of protection.”

The study plan has been submitted to the Food and Drug Administration for review. With FDA allowing it to proceed, the clinical trial will be conducted at seven sites across the United States that participate in NHLBI’s Severe Asthma Research Program.

This program already has a well-characterized group of participants with mild, moderate or severe asthma who may be eligible for this new study.  These groups are largely distinguished by the amount and frequency of glucocorticoids needed to control asthma symptoms. People with mild disease may not need glucocorticoids, or may require low doses of inhaled glucocorticoids; those with moderate asthma need low to moderate doses of inhaled glucocorticoids; and those with severe asthma need high doses of inhaled glucocorticoids and frequently use oral glucocorticoids as well.

Individuals who already have been infected with 2009 H1N1 influenza or have received a 2009 H1N1 influenza vaccination will not be eligible for the study.

“The results of this study will have immediate implications for individuals with severe asthma as well as those who have milder asthma,” says NHLBI Director Elizabeth G. Nabel, M.D.

Early results from other clinical trials of 2009 H1N1 influenza vaccines in healthy adults have shown that a single 15-microgram dose of 2009 H1N1 influenza vaccine without adjuvant is well tolerated and induces a strong immune response in most participants. The same vaccine also generates an immune response that is expected to be protective in healthy children ages 10 to 17 years. Ongoing trials are comparing the immune response to one and two doses of 15- or 30-micrograms of vaccine given three weeks apart in various populations.

The Centers for Disease Control and Prevention has recommended that certain at-risk populations receive the new H1N1 vaccine as a priority before the general population. These target populations include pregnant women, health care providers and individuals with underlying chronic medical conditions, including asthma.

People who have severe asthma may be particularly at risk for infection with the 2009 H1N1 influenza virus. A report published in 2004 suggested that some people who took high doses of glucocorticoids to treat their asthma may receive less protection from influenza vaccines against some strains of influenza.  Early in the 2009 H1N1 flu outbreak a CDC review of hospital records found that people with asthma have a four-fold increased risk of being hospitalized with infection compared to the general population.

The study will enroll approximately 350 people with mild, moderate and severe asthma. Participants will be organized into two groups: those with mild or moderate asthma and those with severe asthma. Half of the participants in each group will receive a 15-microgram dose of vaccine, and the other half a 30-microgram dose.  Three weeks later, each participant will receive a second dose of the same amount. The strength of the immune response induced by the vaccine will be determined in blood samples by measuring the level of antibodies against 2009 H1N1 flu virus.

Safety data will be collected and examined throughout the course of the study by trial investigators and by an independent safety monitoring committee. Participants will be monitored for any side effects they may experience because of the vaccine, as well as asthma attacks that occur during the study period.

The vaccine to be used in the trial, manufactured by Novartis, contains inactivated 2009 H1N1 influenza virus and therefore cannot cause anyone to become infected with the virus.

The trial will be conducted at the following locations:

* Cleveland Clinic, Ohio
* Emory University, Atlanta
* University of Pittsburgh Asthma Institute
* University of Virginia, Charlottesville
* University of Wisconsin, Madison
* Wake Forest University, Winston-Salem, N.C.
* Washington University School of Medicine, St. Louis

Detailed information about this study can be found on the ClinicalTrials.gov website.

Source: National Institute of Allergy and Infectious Diseases

Electron microscope image of the H1N1 influenza virus. Photo: CDC

In a September 15, 2009, update on swine flu vaccines, the U.S. Centers for Disease Control and Prevention noted that live attenuated influenza vaccines should not be given to people with asthma. The CDC announced that four manufacturers were given approval for swine flu (H1N1) vaccines, one of which is a live attenuated influenza vaccine (LAIV) manufactured by MedImmune LLC.

The MedImmune vaccine is approved for persons aged 2 to 49 years, but should not be used to vaccinate certain children and adults, including those with underlying medical conditions that confer a higher risk for influenza complications or children younger than 5 years with one or more episodes of wheezing in the past year, the CDC wrote.

A footnote warned that the vaccine should not be used by asthmatics. It further read:

“Health-care providers should consult the medical record, when available, to identify children aged 2–4 years with asthma or recurrent wheezing that might indicate asthma. In addition, to identify children who might be at greater risk for asthma and possibly at increased risk for wheezing after receiving LAIV, parents or caregivers of children aged 2–4 years should be asked: ‘In the past 12 months, has a health-care provider ever told you that your child had wheezing or asthma?” Children whose parents or caregivers answer “yes” to this question and children who have asthma or who had a wheezing episode noted in the medical record during the preceding 12 months should not receive LAIV.’

Source: Centers for Disease Control and Prevention

According to the Morbidity and Mortality Weekly Report, 67% of children who died with the new H1N1 flu virus had at least one high-risk medical condition.

Any individual with an underlying respiratory condition such as asthma is more likely to experience serious health problems if he or she contracts the flu, according to the American Academy of Allergy, Asthma & Immunology (AAAAI).

“As with seasonal influenza, people with chronic respiratory diseases such as COPD and asthma are more vulnerable to the adverse consequences of H1N1 infection. Recent data suggest that children with asthma are especially at risk and should heed the Centers for Disease Control and Prevention (CDC) recommendations regarding vaccination and treatment options,” said AAAAI Executive Vice President Thomas B. Casale, MD, FAAAAI.

Is it flu or is it allergies?
For parents of children with asthma or allergies, telling the difference between these allergic disease symptoms and the seasonal flu or H1N1 may be a bit difficult. “Itchy eyes, a scratchy nose or sneezing are symptoms of allergies,” Casale suggests. “But if your child suffers from asthma and develops a fever or nausea and vomiting, consult your physician.”

Food allergies and the vaccines
Vaccinations for both the seasonal flu and H1N1 are among the best prevention tools available to prevent complications from the flu, especially for individuals with chronic conditions such as asthma. But what if you are allergic to a substance in the vaccines?

“Individuals with egg allergy may be at risk for an allergic reaction to H1N1 and seasonal influenza vaccines due to the egg content in the vaccine preparations. Before getting vaccinated, review the information posted on www.aaaai.org and consult with your health care provider. In most cases, vaccination can be tolerated if done according to these recommendations,” reports Casale.