Monday, August 31, 2009

Swine flu’s re-emergence: Questions and answers


Swine flu is expected to re-emerge potent and pervasive this fall, infecting as much as half the U.S. population, hospitalizing 2 million people and killing up to 90,000, according to federal officials.

Like pandemic strains of the past, H1N1 has a predilection for infecting young people. And because schools and colleges have long served as veritable cauldrons of flu activity, the combination of a new strain and the opportunity for its spread pose new concerns.

Yet neither state nor federal health officials are recommending surgical masks be added to backpacks when kids return to school. Instead, experts are urging a swine flu vaccination when it’s ready, a seasonal flu vaccination now, and developing a family pandemic plan.

Public health experts say preparedness is the best weapon against an infection that has already hit more than 1 million people in the United States, hospitalized 7,983 and killed 522. Yet given influenza’s extraordinary unpredictability, flu scientists can’t say for sure what the upcoming season will be like.

Is it certain H1N1 will recur in the fall?

Yes. Worldwide surveillance shows H1N1 as the predominant strain circling the globe. Low levels of flu activity are being reported nationwide and all of it is H1N1. Usually at this time of year, there is virtually no flu present, so even low-level activity is uncommon. With so much H1N1 in circulation globally, computer modeling suggests the potential for a strong resurgence.

Will H1N1 become more virulent?

No one can say with certainty. Influenza — especially pandemic flu — is highly unpredictable. Based on what physicians have seen to date, the majority of cases have been mild illnesses of only a few days’ duration.

What are the symptoms?

Identical to seasonal flu: high fever, muscle aches, dry cough and general malaise. Anyone with the flu is urged to stay home during the illness. State and federal health guidelines recommend not returning to school until 24 hours after fever has subsided without the aid of fever-reducing medication.

How does H1N1 differ from seasonal flu?

The virus has a novel gene arrangement that is new to human populations worldwide. It also behaves differently from seasonal flu, which has its greatest impact on the elderly. H1N1 disproportionately affects young people, particularly pregnant women, newborns and people up to 24 years old.

Why are people of school and college age so vulnerable?

It is a new virus that has never been encountered by the human immune system, which means no natural defense. Pandemic strains historically have a greater impact on young, robust people. Opportunity also plays a role. Flu strains tend to proliferate in schools and colleges because people are in close contact. Poor hygiene — coughing, sneezing into a hand — then touching objects that others handle helps spread the virus.

How can parents help children guard against swine flu?

Stress the importance of hygiene. Frequent hand washing and/or use of alcohol-based hand sanitizers are helpful. Public health experts recommend packing a container of hand sanitizer, which can be used when students can’t be excused to use soap and water.

Will schools close when one or two cases are confirmed?

No. New federal guidelines stress the importance of keeping schools open. Long Island school district officials say their aim is to keep schools running as usual. Less H1N1 data was available during the spring when several school closures were ordered. Scientists have since learned H1N1’s infectiousness is comparable to seasonal flu and that the vast majority of people who contract it recover quickly.

Should medically fragile children avoid school entirely this year?

Children who are ventilator-dependent, or who have muscular dystrophy, cerebral palsy or other medical conditions, are being encouraged to attend school. Schools for these children as well as those for pregnant teens face different school-closure recommendations. Unlike mainstream schools, state and federal guidelines recommend closure of schools for medically fragile children when even a single case emerges.

Will there be a vaccine?

Yes. A vaccine is in clinical trials at several centers around the country and is expected by mid-October. Flu scientists are testing the vaccine in pediatric populations.

Will there be enough vaccine for everybody?

No. Health authorities originally had hoped for 120 million doses, but the five manufacturers supplying the United States estimate about 45 million will be available by October. However, manufacturers will continue producing H1N1 vaccines throughout the fall and winter.

Why is the vaccine in short supply?

Flu vaccine production is a long, laborious process. Generally, it requires about nine months to produce seasonal flu vaccines. The H1N1 vaccine is new and requires clinical safety and efficacy testing, which takes time. However, because scientists were able to quickly identify the virus, which is needed as “seed stock” to make the doses, it is helping manufacturers fast-track production even as clinical testing is under way.

Are children and young adults first in line for vaccination?

Yes. Priority groups include: pregnant women; household contacts of infants younger than 6 months old; children and young adults 6 months to 24 years; health care and emergency service workers; and people 25-64 with medical problems, such as asthma, heart disease, diabetes, cancer, etc. Government health officials estimate those groups total 159 million people.

How safe is the vaccine?

Data emerging from clinical trials suggest the vaccine is both safe and effective.

How many doses are required?

The H1N1 flu vaccine is a two-dose immunization taken three weeks apart. Full immunity occurs about two weeks after the second dose. For most people receiving the vaccine, immunity probably won’t be achieved until Thanksgiving or later.

Will the vaccine contain the preservative thimerosal?

Some H1N1 vaccines will contain thimerosal, a chemical preservative activists have linked to autism. However, there is no scientific basis for that claim. Manufacturers are also producing thimerosal-free doses. If you have concerns, ask your child’s physician for a thimerosal-free vaccine.

Once you are exposed to swine flu or already sick, are antiviral drugs effective?

Yes. They can shorten the course of influenza. But they have to be judiciously prescribed. Currently, there are no dramatic signs of drug resistance. But public health agencies urge caution because only two medications are available to treat swine flu: Tamiflu (oseltamivir) and Relenza (zanamivir). Tamiflu when taken within 48 hours of flu exposure can prevent infection. Misuse of either medication can lead to resistance, making the drugs useless.

Who should take an antiviral?

The World Health Organization says otherwise healthy people with mild to moderate cases of swine flu do not need an antiviral. But anyone who is young, old, pregnant or has an underlying health problem can benefit.

If you had swine flu during the outbreak last spring, should you get the new vaccine?

No. If you had a confirmed diagnosis of H1N1, that infection should provide immunity.

What about if the case was not confirmed?

If you fall into one of the targeted groups, but the case wasn’t confirmed, you should consult a physician.


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