s. korea

Children and Influenza

A plan for controlling a possible influenza pandemic published by the federal Department of Health and Human Services (HHS) in November is silent on one important point—if a vaccine is developed against a potentially deadly influenza strain, who will receive it? Will public health officials and care providers be told to give the vaccine to the elderly, on the grounds that they are most likely to experience complications if they contract the flu? Or is it possible that the vaccine—which is sure to be scarce in the early days of a pandemic--might be used instead to immunize children, on the theory that medicine has an obligation to "save the future generation"?

The most deadly flu pandemic in recent times was the 1919 "Spanish flu" which killed millions of people worldwide in the years following World War I. That strain of the flu seemed to target healthy young and middle-aged persons, and widespread infections began with young men in the military services. Whether a new strain of the influenza virus would behave the same way is unknown, but the avian flu now circulating in the Far East has already claimed several child victims, some as young as seven years, making it thinkable that a pandemic would seriously affect children worldwide.

That children can become very ill and even die from complications of influenza was indicated in a report published in the November 2 issue of the Journal of the American Medical Association, in which researchers looked at the hospital records of children who were hospitalized with community-acquired, laboratory-confirmed influenza in Philadelphia in the years 2000-2004. Some of the children in the study had underlying conditions such as asthma, chronic pulmonary disease, cardiac disease, and neurological and neuromuscular disorders that may have made their conditions more precarious, but others had been previously healthy. For all of the children, the researchers found the most common complication of influenza to be respiratory failure, followed in some cases by cardiac arrest and death.

But a decision about whether or not to vaccinate children has another dimension, as well. It is believed that children are vectors—the "typhoid Mary’s"—of the influenza virus, harboring and transmitting the virus to adults with whom they come into contact, even if the children themselves are not ill. If that is the case, the argument goes, the logical way to stop the spread of a deadly influenza would be to vaccinate children. And since a vaccine would not be immediately available at the start of a pandemic, it would seem logical in the meantime to close schools, day care centers, libraries, and other sites where children and adults meet.

The Centers for Disease Control and Prevention (CDC) acknowledges that there will be a time lag after the onset of a pandemic before a vaccine is available. That’s because we won’t know before we see it what strain of the influenza virus is causing the pandemic, and once we know, it will take at least six months to produce a vaccine, using current laboratory techniques that involve cultivating flu vaccines in chicken eggs, a time-consuming process. The CDC has conceded that in the interval between onset of a pandemic and the availability of a vaccine, many people, including children, will become ill and an unpredictable number will die.

During that time, the CDC is recommending that people take anti-viral medications that may limit the severity of the influenza. The most prominently mentioned of those medications is Tamiflu (oseltamivir phosphate), and the federal government has said it is stockpiling enough supplies of that product to treat one-quarter of the U.S. population. While it has not been studied specifically for use in a pandemic, Tamiflu is currently approved for the treatment of uncomplicated influenza A and B in patients one year of age and older and for possible prophylaxis of persons 13 and older at high risk of exposure in a normal influenza season. The drug acts by blocking the viral enzyme neuraminidsae, which helps the influenza vaccine invade cells in the respiratory tract. It’s available in both capsule and liquid formulations and is dosed according to body weight in younger children, with older children (over 88 pounds) and adolescents receiving the same dose as adults. When used twice daily for five days, Tamiflu can reduce the duration of influenza symptoms in otherwise healthy children by one to one-and-a-half days, allowing children to return to school sooner.

A federal Food and Drug Administration (FDA) meeting November 18 to review possible adverse effects of drugs that have been given extended copyright protection because the makers are conducting pediatric clinical trials, was told of pediatric deaths, serious skin reactions, and neuropsychiatric events from Tamiflu, reported almost entirely in children from Japan, where dosage recommendations are similar to those in the United States. The FDA said it has requested additional information from both Hoffman-LaRoche, the pharmaceutical company that produces Tamiflu, and the Japanese Ministry of Health and is evaluating possible reasons for the reported adverse events, which have prompted nationwide surveillance of Tamiflu in children in Japan, which currently uses the majority of the world’s supply of Tamiflu for treatment of seasonal influenza. The FDA said it is concerned to know whether the Japanese effects might be seen in this country, as well, if use of Tamiflu increases here, but at the moment there is no additional restriction on prescription of the drug.

The Plan

Here are excerpts from the "HHS Pandemic Preparation Plan" published in November.

A pandemic occurs when a novel influenza virus emerges that can infect and be efficiently transmitted among individuals because of a lack of pre-existing immunity in the population. The extent and severity of the pandemic depends on the specific characteristics of the virus. Although a novel influenza virus could emerge from anywhere in the world at any time, scientists are particularly concerned about the avian influenza (H5N1) currently circulating in Asia and parts of Europe. The H5N1 avian influenza virus is widespread in the region and has become endemic in migratory birds and several other animal species. As of October 2005, cases of human H5N1 infection have been reported in Thailand, Vietnam, Cambodia, and Indonesia. The reported death rate for these cases has been 50 percent.

Sustained human-to-human transmission anywhere in the world will be the triggering event to initiate a pandemic response by the United States. When possible and appropriate, protective public health measures will be employed to reduce person-to-person viral transmission and to prevent or delay influenza outbreaks. At the onset of a pandemic, vaccine, which will initially be in short supply, will be procured by HHS and distributed to state and local health departments for immunization of pre-determined priority groups. At the onset of a pandemic, antiviral drugs from public stockpiles will be distributed to health care providers for administration to pre-determined priority groups. HHS will work with state and local governments to develop guidelines and operational plans for distribution of available supplies of a pandemic vaccine and antiviral drugs.

The full text of "HHS Pandemic Influenza Plan" is available online at http://www.hhs.gov/pandemicflu/plan.

See also Flu Season and Schools at http://www.healthinschools.org/sh/influenza.asp and Avian Flu Fact Sheet at http://www.healthinschools.org/sh/Avianflu.asp.

Experts Cite Physical Activity as Key in Preventing Childhood Obesity