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Monitor the 2009-H1N1 Influenza Outbreak

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We are learning more daily about the 2009-H1N1 influenza, now also called the novel H1N1 flu, as the outbreak unfolds. It will be critical for us as clinicians to stay on top of developments so that we can tailor our patient care accordingly. Although disease activity seems to be decreasing, taking what we know today and preparing for fall is imperative.

As the name suggests, this strain of the virus has never circulated in the population before, but there has been some speculation that the low rate of disease in persons older than age 50 years may relate to circulation of a closely related strain decades ago.

Public health officials' main concern has been that with a large susceptible population, the outbreak will evolve into a major global pandemic with high morbidity and mortality, as occurred in 1918. Estimates from the Centers for Disease Control and Prevention suggest that even if this outbreak is a moderate one, up to 35% of the U.S. population could be infected and up to 207,000 people could die.

What is important to us as pediatricians is that in times of pandemic flu, mortality has been highest among the young and healthy. Some investigators propose as an explanation that the virus provokes a cytokine storm in people with a robust immune system, resulting in a kind of immunologic paralysis. Indeed, initial reports from Mexico suggested that most flu deaths were occurring in otherwise healthy individuals; authorities there are now reviewing their data to better assess who may be at greatest risk.

The clinical picture of influenza is usually easy to recognize: an abrupt onset of fever, cough, sore throat, and rhinitis. In a recent study from Finland, myalgia and headache were less common in children than they were in adults. At our institution, in the recent outbreak, we have gotten more selective about which children we test for influenza because we found that using the CDC criteria of a fever of at least 37.8° C and a runny nose, we picked up a lot of common colds and croup. In our first 15 pediatric cases of this flu, the mean fever was much higher at 39.8° C. So the low-grade fever used to guide testing in adults is probably not going to be reliable in children.

Another discovery has been that our rapid influenza test is not sensitive for the H1N1 virus; therefore, such testing may not aid in diagnosis. The take-home message is that it's wise to check with your local infectious disease specialists about the diagnostic performance of the rapid test used by your laboratory. In contrast, we have found that the multiplex polymerase chain reaction test that we use has reliably picked up all cases of H1N1 flu, although it identifies them as influenza A isolates that are not able to be subtyped using standard H1N1 primers.

Education will be key in responding to this outbreak. The worried well are flocking to their doctors' offices and sitting in waiting rooms next to those with mild influenza, who also don't need to be there. At our institution, we are distributing a handout to parents that explains that influenza testing and antiviral therapy are not needed for mild influenza. We instruct them in how to provide home care and about warning signs that mean they should seek care for their child.

At this point, antiviral therapy among children with influenza is mainly being restricted to those admitted to the hospital and those at high risk for complications. The latter group includes, among others, children younger than age 5 years, but particularly those younger than age 2. If more than 48 hours have elapsed since symptom onset, the therapy may have little effect, so symptomatic management alone is reasonable. Antiviral prophylaxis should be considered for exposed siblings who are at high risk for influenza complications.

Pediatricians need to be vigilant and prepared for the known possible complications of influenza, especially superinfection including bacterial pneumonia. Some of the less common complications can have tricky presentations in the pediatric population. For example, in children, influenza-related encephalopathy can manifest as aphasia, and in some children with influenza-associated myositis, parents may contact their provider with the concern that their child has an acute onset of paralysis as the child refuses to walk.

In contrast to adults with influenza, who are infectious to others for roughly 6 days, children are infectious for at least 10 days. This is going to be problematic because it may be necessary to maintain barrier protection for hospitalized children for longer than a week.

 

 

The novel H1N1 outbreak has clearly been taxing the health care system and health care providers, especially on the outpatient side. Although we have been preparing for such an event for years, several logistical problems have emerged. One is a shortage of N95 masks, a required piece of personal protective equipment when caring for hospitalized patients with pandemic influenza. Another is a shortage of staff, as personnel with suspected or confirmed infection must stay home.

We are anticipating that a vaccine against the 2009-H1N1 virus could be available by September or October. It's likely going to require two shots, in addition to the standard seasonal influenza shot. This might be a hard sell to vaccine-hesitant parents under usual circumstances, but it is too soon to tell what the reception will be like in the context of the current outbreak.

Public health officials are hoping transmission of the virus will decrease naturally with the end of the school year. However, resurgence of the 2009-H1N1 disease in the fall is a possibility that we need to be prepared for, particularly if new mutations increase its virulence.

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[email protected]

We are learning more daily about the 2009-H1N1 influenza, now also called the novel H1N1 flu, as the outbreak unfolds. It will be critical for us as clinicians to stay on top of developments so that we can tailor our patient care accordingly. Although disease activity seems to be decreasing, taking what we know today and preparing for fall is imperative.

As the name suggests, this strain of the virus has never circulated in the population before, but there has been some speculation that the low rate of disease in persons older than age 50 years may relate to circulation of a closely related strain decades ago.

Public health officials' main concern has been that with a large susceptible population, the outbreak will evolve into a major global pandemic with high morbidity and mortality, as occurred in 1918. Estimates from the Centers for Disease Control and Prevention suggest that even if this outbreak is a moderate one, up to 35% of the U.S. population could be infected and up to 207,000 people could die.

What is important to us as pediatricians is that in times of pandemic flu, mortality has been highest among the young and healthy. Some investigators propose as an explanation that the virus provokes a cytokine storm in people with a robust immune system, resulting in a kind of immunologic paralysis. Indeed, initial reports from Mexico suggested that most flu deaths were occurring in otherwise healthy individuals; authorities there are now reviewing their data to better assess who may be at greatest risk.

The clinical picture of influenza is usually easy to recognize: an abrupt onset of fever, cough, sore throat, and rhinitis. In a recent study from Finland, myalgia and headache were less common in children than they were in adults. At our institution, in the recent outbreak, we have gotten more selective about which children we test for influenza because we found that using the CDC criteria of a fever of at least 37.8° C and a runny nose, we picked up a lot of common colds and croup. In our first 15 pediatric cases of this flu, the mean fever was much higher at 39.8° C. So the low-grade fever used to guide testing in adults is probably not going to be reliable in children.

Another discovery has been that our rapid influenza test is not sensitive for the H1N1 virus; therefore, such testing may not aid in diagnosis. The take-home message is that it's wise to check with your local infectious disease specialists about the diagnostic performance of the rapid test used by your laboratory. In contrast, we have found that the multiplex polymerase chain reaction test that we use has reliably picked up all cases of H1N1 flu, although it identifies them as influenza A isolates that are not able to be subtyped using standard H1N1 primers.

Education will be key in responding to this outbreak. The worried well are flocking to their doctors' offices and sitting in waiting rooms next to those with mild influenza, who also don't need to be there. At our institution, we are distributing a handout to parents that explains that influenza testing and antiviral therapy are not needed for mild influenza. We instruct them in how to provide home care and about warning signs that mean they should seek care for their child.

At this point, antiviral therapy among children with influenza is mainly being restricted to those admitted to the hospital and those at high risk for complications. The latter group includes, among others, children younger than age 5 years, but particularly those younger than age 2. If more than 48 hours have elapsed since symptom onset, the therapy may have little effect, so symptomatic management alone is reasonable. Antiviral prophylaxis should be considered for exposed siblings who are at high risk for influenza complications.

Pediatricians need to be vigilant and prepared for the known possible complications of influenza, especially superinfection including bacterial pneumonia. Some of the less common complications can have tricky presentations in the pediatric population. For example, in children, influenza-related encephalopathy can manifest as aphasia, and in some children with influenza-associated myositis, parents may contact their provider with the concern that their child has an acute onset of paralysis as the child refuses to walk.

In contrast to adults with influenza, who are infectious to others for roughly 6 days, children are infectious for at least 10 days. This is going to be problematic because it may be necessary to maintain barrier protection for hospitalized children for longer than a week.

 

 

The novel H1N1 outbreak has clearly been taxing the health care system and health care providers, especially on the outpatient side. Although we have been preparing for such an event for years, several logistical problems have emerged. One is a shortage of N95 masks, a required piece of personal protective equipment when caring for hospitalized patients with pandemic influenza. Another is a shortage of staff, as personnel with suspected or confirmed infection must stay home.

We are anticipating that a vaccine against the 2009-H1N1 virus could be available by September or October. It's likely going to require two shots, in addition to the standard seasonal influenza shot. This might be a hard sell to vaccine-hesitant parents under usual circumstances, but it is too soon to tell what the reception will be like in the context of the current outbreak.

Public health officials are hoping transmission of the virus will decrease naturally with the end of the school year. However, resurgence of the 2009-H1N1 disease in the fall is a possibility that we need to be prepared for, particularly if new mutations increase its virulence.

[email protected]

We are learning more daily about the 2009-H1N1 influenza, now also called the novel H1N1 flu, as the outbreak unfolds. It will be critical for us as clinicians to stay on top of developments so that we can tailor our patient care accordingly. Although disease activity seems to be decreasing, taking what we know today and preparing for fall is imperative.

As the name suggests, this strain of the virus has never circulated in the population before, but there has been some speculation that the low rate of disease in persons older than age 50 years may relate to circulation of a closely related strain decades ago.

Public health officials' main concern has been that with a large susceptible population, the outbreak will evolve into a major global pandemic with high morbidity and mortality, as occurred in 1918. Estimates from the Centers for Disease Control and Prevention suggest that even if this outbreak is a moderate one, up to 35% of the U.S. population could be infected and up to 207,000 people could die.

What is important to us as pediatricians is that in times of pandemic flu, mortality has been highest among the young and healthy. Some investigators propose as an explanation that the virus provokes a cytokine storm in people with a robust immune system, resulting in a kind of immunologic paralysis. Indeed, initial reports from Mexico suggested that most flu deaths were occurring in otherwise healthy individuals; authorities there are now reviewing their data to better assess who may be at greatest risk.

The clinical picture of influenza is usually easy to recognize: an abrupt onset of fever, cough, sore throat, and rhinitis. In a recent study from Finland, myalgia and headache were less common in children than they were in adults. At our institution, in the recent outbreak, we have gotten more selective about which children we test for influenza because we found that using the CDC criteria of a fever of at least 37.8° C and a runny nose, we picked up a lot of common colds and croup. In our first 15 pediatric cases of this flu, the mean fever was much higher at 39.8° C. So the low-grade fever used to guide testing in adults is probably not going to be reliable in children.

Another discovery has been that our rapid influenza test is not sensitive for the H1N1 virus; therefore, such testing may not aid in diagnosis. The take-home message is that it's wise to check with your local infectious disease specialists about the diagnostic performance of the rapid test used by your laboratory. In contrast, we have found that the multiplex polymerase chain reaction test that we use has reliably picked up all cases of H1N1 flu, although it identifies them as influenza A isolates that are not able to be subtyped using standard H1N1 primers.

Education will be key in responding to this outbreak. The worried well are flocking to their doctors' offices and sitting in waiting rooms next to those with mild influenza, who also don't need to be there. At our institution, we are distributing a handout to parents that explains that influenza testing and antiviral therapy are not needed for mild influenza. We instruct them in how to provide home care and about warning signs that mean they should seek care for their child.

At this point, antiviral therapy among children with influenza is mainly being restricted to those admitted to the hospital and those at high risk for complications. The latter group includes, among others, children younger than age 5 years, but particularly those younger than age 2. If more than 48 hours have elapsed since symptom onset, the therapy may have little effect, so symptomatic management alone is reasonable. Antiviral prophylaxis should be considered for exposed siblings who are at high risk for influenza complications.

Pediatricians need to be vigilant and prepared for the known possible complications of influenza, especially superinfection including bacterial pneumonia. Some of the less common complications can have tricky presentations in the pediatric population. For example, in children, influenza-related encephalopathy can manifest as aphasia, and in some children with influenza-associated myositis, parents may contact their provider with the concern that their child has an acute onset of paralysis as the child refuses to walk.

In contrast to adults with influenza, who are infectious to others for roughly 6 days, children are infectious for at least 10 days. This is going to be problematic because it may be necessary to maintain barrier protection for hospitalized children for longer than a week.

 

 

The novel H1N1 outbreak has clearly been taxing the health care system and health care providers, especially on the outpatient side. Although we have been preparing for such an event for years, several logistical problems have emerged. One is a shortage of N95 masks, a required piece of personal protective equipment when caring for hospitalized patients with pandemic influenza. Another is a shortage of staff, as personnel with suspected or confirmed infection must stay home.

We are anticipating that a vaccine against the 2009-H1N1 virus could be available by September or October. It's likely going to require two shots, in addition to the standard seasonal influenza shot. This might be a hard sell to vaccine-hesitant parents under usual circumstances, but it is too soon to tell what the reception will be like in the context of the current outbreak.

Public health officials are hoping transmission of the virus will decrease naturally with the end of the school year. However, resurgence of the 2009-H1N1 disease in the fall is a possibility that we need to be prepared for, particularly if new mutations increase its virulence.

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