Pandemic influenza: How it would progress and what it would require of you

An influenza pandemic, or world-wide outbreak, advances through 3 periods—interpandemic, pandemic alert, and pandemic—and their respective phases defined by the World Health Organization (TABLE 1). Your responsibilities would be different in each of these periods (TABLE 2), requiring you to stay current on the progression of the disease and changing recommendations coming from the Centers for Disease Control and Prevention (CDC) and state and local public health departments.

A pandemic would be caused by the emergence of a new strain of influenza A. This strain could be the avian strain described in the May 2005 Practice Alert,¹ “The growing threat of avian influenza,”or another novel strain.

This column describes the family physician’s role in a pandemic and includes advice on diagnosis, treatment, and prevention of disease transmission. It is based on recent recommendations from the CDC.²

Major differences between pandemic flu and a regular flu season

Vaccine shortage. Unless faster vaccine production methods are developed, there will probably be little to no vaccine initially, and once vaccine production commences the amount produced will not keep up with the need. This will necessitate prioritizing vaccine administration, forcing us to weigh societal infrastructure needs (fire-fighters, health care workers, police, etc) against those of individuals at high risk of complications.

In addition, 2 doses of vaccine 1 month apart will be needed for full protection. (Note: There is an approved provisional plan through the Advisory Committee on Immunization Practices [ACIP] and the National Vaccine Advisory Committee [NVAC] for vaccine prioritization.)

Antiviral shortage. There will also likely be a shortage of antiviral medication. Amantadine (Symmetrel) and rimantadine (Flumadine)—antivirals recommended for use against influenza A—have reduced efficacy against avian influenza, and the same may be true with any other novel strain.

Other antivirals if they are effective and available, will be used to treat acute infections and to prevent infection in those exposed and/or at high risk of complications and will be administered according to a prioritization schedule. Recommendations for prioritization of both vaccine and antivirals will come from ACIP/NVAC and the Secretary of the Department of Health and Human Services. The recommendations will be implemented by the CDC and state and local health departments, but may change as the pandemic evolves, depending on the number of people and age groups infected and the rates of morbidity and mortality.

Complicating factors. A common influenza strain could circulate at the same time as a pandemic strain, complicating the diagnostic and epidemiological picture. Office-based, rapid diagnostic tests cannot distinguish between influenza A strains. Finally, if pandemic flu exhibits the expected high rates of proliferation and mortality seen in past pandemics, our current hospital capacity will be strained and likely exceeded.

TABLE 1
WHO global pandemic phases

TABLE 2
Family physician responsibilities

Back to basics

Even with a limited supply of vaccine and antiviral medication, useful advice can still be given to individuals and the public to help them protect them and others from infection should a pandemic occur. People should be advised to:

• What hands frequently and thoroughly
• Avoid locations where infection is likely to occur
• Avoid close contact with those who have flu-like symptoms
• Cover coughs and sneezes with tissues, properly dispose of used tissue, and wash hands after handling waste
• Use infection control measures in the home if a household member is ill (TABLE 3)
• Possibly use masks. (No consensus exists on the use of masks by those infected or potentially exposed. Surgical masks may be useful for providers of patient care.)

Physicians can take measures to minimize the chance of spreading the virus in their clinics and to protect themselves and other staff (covered in a previous Practice Alert).³ Infection control guidelines can be implemented in hospitals and other health care facilities, as well as in schools and other high-risk settings.

TABLE 3
Infection control measures for patients cared for at home

Clinical guidelines: Pandemic alert

The recommended clinical approach to a patient suspected of having a novel flu strain will vary depending on the phase of the pandemic.

Through phase 5, in the pandemic alert period, acute febrile respiratory illness will be caused by a novel influenza virus only rarely. Suspect novel influenza only if the patient meets both clinical and epidemiologic criteria. The clinical criteria are fever plus 1 or more of the following: sore throat, cough, dyspnea.

Epidemiologic criteria include travel within the past 10 days to an area affected by highly pathogenic avian influenza out-breaks in poultry or where human cases of novel influenza have been confirmed; and either direct contact with poultry (touching birds or bird feces or surfaces contaminated by bird feces or eating uncooked poultry products) or close contact with a person with confirmed or suspected novel influenza. Occupational exposure through laboratory work with the novel influenza strain would also be considered an epidemiologic criterion, but this occurrence would be rare. Geographic areas affected by avian influenza can be found on the CDC web site (www.cdc.gov/flu/) and World Health Organization web site (www.who.int.en/).

6 Steps to proper management. Once a patient is suspected of having a novel influenza strain, take the following steps.

1. Control spread of infection. Consider admitting the patient to a single-patient hospital room. If this is not possible, take precautions to control infection in the home (TABLE 3). Details of hospital infection control precautions can be found on the CDC influenza web site.
2. Notify local or state public health departments. Report the suspicious case and ask for advice regarding collecting laboratory specimens and treatment options.
3. Obtain clinical specimens requested by the public health department and arrange to have them transported to a designated public health laboratory. These will probably consist of a nasopharyngeal swab, nasal swab, throat swab, and an acute serum specimen (for comparison to a convalescent specimen 2 to 3 weeks later).
4. Evaluate alternative diagnoses. Remember that a novel influenza infection can co-infect with a more common organism. Discontinue isolation and antiviral therapy prematurely only if an alternative diagnosis is confirmed with a high-predictive value test, the clinical course is explained by the alternative diagnosis, and the epidemiologic link to the novel influenza strain is not strong.
5. Start antiviral treatment.
6. Assist the public health department in locating potentially exposed contacts and providing antiviral prophylaxis if recommended.

Clinical guidelines: Pandemic period

During the pandemic period, managing suspected infection differs from the pandemic alert period in several respects.

1. Suspected cases need only meet the clinical criteria: fever with sore throat, cough, or dyspnea. These criteria may be modified as the pandemic evolves.
2. Hospitalize only those patients with severe complications who cannot be cared for at home.
3. Submit clinical specimens to the designated lab only as requested by the public health department. Such monitoring will probably be needed only for a subset of patients to watch the epidemiology of the epidemic or to investigate unusual presentations or failures of preventive therapy.
4. Report atypical cases, prophylaxis failures, and other abnormal cases to the public health department.

Pre-pandemic planning

If and when another influenza pandemic will occur is difficult to predict. To be prepared, follow sound public health practices: adhere to office infection control practices, insure that patients and staff are current on all immunizations—influenza and pneumococcal vaccines can probably limit the complications from a novel influenza pandemic—maintain a line of communication with the local public health department, report communicable diseases and suspicious presentations to the public health department, and participate in local emergency planning.

Family physicians who serve in leadership positions in hospitals and other health care facilities can also promote planning for a possible pandemic at these facilities, including how to manage a surge of critically ill patients.

CORRESPONDING AUTHOR
Doug Campos-Outcalt, MD, MPA, 4001 North Third Street #415, Phoenix, AZ 85012. E-mail: [email protected]

An influenza pandemic, or world-wide outbreak, advances through 3 periods—interpandemic, pandemic alert, and pandemic—and their respective phases defined by the World Health Organization (TABLE 1). Your responsibilities would be different in each of these periods (TABLE 2), requiring you to stay current on the progression of the disease and changing recommendations coming from the Centers for Disease Control and Prevention (CDC) and state and local public health departments.

A pandemic would be caused by the emergence of a new strain of influenza A. This strain could be the avian strain described in the May 2005 Practice Alert,¹ “The growing threat of avian influenza,”or another novel strain.

This column describes the family physician’s role in a pandemic and includes advice on diagnosis, treatment, and prevention of disease transmission. It is based on recent recommendations from the CDC.²

Major differences between pandemic flu and a regular flu season

Vaccine shortage. Unless faster vaccine production methods are developed, there will probably be little to no vaccine initially, and once vaccine production commences the amount produced will not keep up with the need. This will necessitate prioritizing vaccine administration, forcing us to weigh societal infrastructure needs (fire-fighters, health care workers, police, etc) against those of individuals at high risk of complications.

In addition, 2 doses of vaccine 1 month apart will be needed for full protection. (Note: There is an approved provisional plan through the Advisory Committee on Immunization Practices [ACIP] and the National Vaccine Advisory Committee [NVAC] for vaccine prioritization.)

Antiviral shortage. There will also likely be a shortage of antiviral medication. Amantadine (Symmetrel) and rimantadine (Flumadine)—antivirals recommended for use against influenza A—have reduced efficacy against avian influenza, and the same may be true with any other novel strain.

Other antivirals if they are effective and available, will be used to treat acute infections and to prevent infection in those exposed and/or at high risk of complications and will be administered according to a prioritization schedule. Recommendations for prioritization of both vaccine and antivirals will come from ACIP/NVAC and the Secretary of the Department of Health and Human Services. The recommendations will be implemented by the CDC and state and local health departments, but may change as the pandemic evolves, depending on the number of people and age groups infected and the rates of morbidity and mortality.

Complicating factors. A common influenza strain could circulate at the same time as a pandemic strain, complicating the diagnostic and epidemiological picture. Office-based, rapid diagnostic tests cannot distinguish between influenza A strains. Finally, if pandemic flu exhibits the expected high rates of proliferation and mortality seen in past pandemics, our current hospital capacity will be strained and likely exceeded.

TABLE 1
WHO global pandemic phases

TABLE 2
Family physician responsibilities

Back to basics

Even with a limited supply of vaccine and antiviral medication, useful advice can still be given to individuals and the public to help them protect them and others from infection should a pandemic occur. People should be advised to:

• What hands frequently and thoroughly
• Avoid locations where infection is likely to occur
• Avoid close contact with those who have flu-like symptoms
• Cover coughs and sneezes with tissues, properly dispose of used tissue, and wash hands after handling waste
• Use infection control measures in the home if a household member is ill (TABLE 3)
• Possibly use masks. (No consensus exists on the use of masks by those infected or potentially exposed. Surgical masks may be useful for providers of patient care.)

Physicians can take measures to minimize the chance of spreading the virus in their clinics and to protect themselves and other staff (covered in a previous Practice Alert).³ Infection control guidelines can be implemented in hospitals and other health care facilities, as well as in schools and other high-risk settings.

TABLE 3
Infection control measures for patients cared for at home

Clinical guidelines: Pandemic alert

The recommended clinical approach to a patient suspected of having a novel flu strain will vary depending on the phase of the pandemic.

Through phase 5, in the pandemic alert period, acute febrile respiratory illness will be caused by a novel influenza virus only rarely. Suspect novel influenza only if the patient meets both clinical and epidemiologic criteria. The clinical criteria are fever plus 1 or more of the following: sore throat, cough, dyspnea.

Epidemiologic criteria include travel within the past 10 days to an area affected by highly pathogenic avian influenza out-breaks in poultry or where human cases of novel influenza have been confirmed; and either direct contact with poultry (touching birds or bird feces or surfaces contaminated by bird feces or eating uncooked poultry products) or close contact with a person with confirmed or suspected novel influenza. Occupational exposure through laboratory work with the novel influenza strain would also be considered an epidemiologic criterion, but this occurrence would be rare. Geographic areas affected by avian influenza can be found on the CDC web site (www.cdc.gov/flu/) and World Health Organization web site (www.who.int.en/).

6 Steps to proper management. Once a patient is suspected of having a novel influenza strain, take the following steps.

1. Control spread of infection. Consider admitting the patient to a single-patient hospital room. If this is not possible, take precautions to control infection in the home (TABLE 3). Details of hospital infection control precautions can be found on the CDC influenza web site.
2. Notify local or state public health departments. Report the suspicious case and ask for advice regarding collecting laboratory specimens and treatment options.
3. Obtain clinical specimens requested by the public health department and arrange to have them transported to a designated public health laboratory. These will probably consist of a nasopharyngeal swab, nasal swab, throat swab, and an acute serum specimen (for comparison to a convalescent specimen 2 to 3 weeks later).
4. Evaluate alternative diagnoses. Remember that a novel influenza infection can co-infect with a more common organism. Discontinue isolation and antiviral therapy prematurely only if an alternative diagnosis is confirmed with a high-predictive value test, the clinical course is explained by the alternative diagnosis, and the epidemiologic link to the novel influenza strain is not strong.
5. Start antiviral treatment.
6. Assist the public health department in locating potentially exposed contacts and providing antiviral prophylaxis if recommended.

Clinical guidelines: Pandemic period

During the pandemic period, managing suspected infection differs from the pandemic alert period in several respects.

1. Suspected cases need only meet the clinical criteria: fever with sore throat, cough, or dyspnea. These criteria may be modified as the pandemic evolves.
2. Hospitalize only those patients with severe complications who cannot be cared for at home.
3. Submit clinical specimens to the designated lab only as requested by the public health department. Such monitoring will probably be needed only for a subset of patients to watch the epidemiology of the epidemic or to investigate unusual presentations or failures of preventive therapy.
4. Report atypical cases, prophylaxis failures, and other abnormal cases to the public health department.

Pre-pandemic planning

If and when another influenza pandemic will occur is difficult to predict. To be prepared, follow sound public health practices: adhere to office infection control practices, insure that patients and staff are current on all immunizations—influenza and pneumococcal vaccines can probably limit the complications from a novel influenza pandemic—maintain a line of communication with the local public health department, report communicable diseases and suspicious presentations to the public health department, and participate in local emergency planning.

Family physicians who serve in leadership positions in hospitals and other health care facilities can also promote planning for a possible pandemic at these facilities, including how to manage a surge of critically ill patients.

CORRESPONDING AUTHOR
Doug Campos-Outcalt, MD, MPA, 4001 North Third Street #415, Phoenix, AZ 85012. E-mail: [email protected]

An influenza pandemic, or world-wide outbreak, advances through 3 periods—interpandemic, pandemic alert, and pandemic—and their respective phases defined by the World Health Organization (TABLE 1). Your responsibilities would be different in each of these periods (TABLE 2), requiring you to stay current on the progression of the disease and changing recommendations coming from the Centers for Disease Control and Prevention (CDC) and state and local public health departments.

A pandemic would be caused by the emergence of a new strain of influenza A. This strain could be the avian strain described in the May 2005 Practice Alert,¹ “The growing threat of avian influenza,”or another novel strain.

This column describes the family physician’s role in a pandemic and includes advice on diagnosis, treatment, and prevention of disease transmission. It is based on recent recommendations from the CDC.²

Major differences between pandemic flu and a regular flu season

Vaccine shortage. Unless faster vaccine production methods are developed, there will probably be little to no vaccine initially, and once vaccine production commences the amount produced will not keep up with the need. This will necessitate prioritizing vaccine administration, forcing us to weigh societal infrastructure needs (fire-fighters, health care workers, police, etc) against those of individuals at high risk of complications.

In addition, 2 doses of vaccine 1 month apart will be needed for full protection. (Note: There is an approved provisional plan through the Advisory Committee on Immunization Practices [ACIP] and the National Vaccine Advisory Committee [NVAC] for vaccine prioritization.)

Antiviral shortage. There will also likely be a shortage of antiviral medication. Amantadine (Symmetrel) and rimantadine (Flumadine)—antivirals recommended for use against influenza A—have reduced efficacy against avian influenza, and the same may be true with any other novel strain.

Other antivirals if they are effective and available, will be used to treat acute infections and to prevent infection in those exposed and/or at high risk of complications and will be administered according to a prioritization schedule. Recommendations for prioritization of both vaccine and antivirals will come from ACIP/NVAC and the Secretary of the Department of Health and Human Services. The recommendations will be implemented by the CDC and state and local health departments, but may change as the pandemic evolves, depending on the number of people and age groups infected and the rates of morbidity and mortality.

Complicating factors. A common influenza strain could circulate at the same time as a pandemic strain, complicating the diagnostic and epidemiological picture. Office-based, rapid diagnostic tests cannot distinguish between influenza A strains. Finally, if pandemic flu exhibits the expected high rates of proliferation and mortality seen in past pandemics, our current hospital capacity will be strained and likely exceeded.

TABLE 1
WHO global pandemic phases

TABLE 2
Family physician responsibilities

Back to basics

Even with a limited supply of vaccine and antiviral medication, useful advice can still be given to individuals and the public to help them protect them and others from infection should a pandemic occur. People should be advised to:

• What hands frequently and thoroughly
• Avoid locations where infection is likely to occur
• Avoid close contact with those who have flu-like symptoms
• Cover coughs and sneezes with tissues, properly dispose of used tissue, and wash hands after handling waste
• Use infection control measures in the home if a household member is ill (TABLE 3)
• Possibly use masks. (No consensus exists on the use of masks by those infected or potentially exposed. Surgical masks may be useful for providers of patient care.)

Physicians can take measures to minimize the chance of spreading the virus in their clinics and to protect themselves and other staff (covered in a previous Practice Alert).³ Infection control guidelines can be implemented in hospitals and other health care facilities, as well as in schools and other high-risk settings.

TABLE 3
Infection control measures for patients cared for at home

Clinical guidelines: Pandemic alert

The recommended clinical approach to a patient suspected of having a novel flu strain will vary depending on the phase of the pandemic.

Through phase 5, in the pandemic alert period, acute febrile respiratory illness will be caused by a novel influenza virus only rarely. Suspect novel influenza only if the patient meets both clinical and epidemiologic criteria. The clinical criteria are fever plus 1 or more of the following: sore throat, cough, dyspnea.

Epidemiologic criteria include travel within the past 10 days to an area affected by highly pathogenic avian influenza out-breaks in poultry or where human cases of novel influenza have been confirmed; and either direct contact with poultry (touching birds or bird feces or surfaces contaminated by bird feces or eating uncooked poultry products) or close contact with a person with confirmed or suspected novel influenza. Occupational exposure through laboratory work with the novel influenza strain would also be considered an epidemiologic criterion, but this occurrence would be rare. Geographic areas affected by avian influenza can be found on the CDC web site (www.cdc.gov/flu/) and World Health Organization web site (www.who.int.en/).

6 Steps to proper management. Once a patient is suspected of having a novel influenza strain, take the following steps.

1. Control spread of infection. Consider admitting the patient to a single-patient hospital room. If this is not possible, take precautions to control infection in the home (TABLE 3). Details of hospital infection control precautions can be found on the CDC influenza web site.
2. Notify local or state public health departments. Report the suspicious case and ask for advice regarding collecting laboratory specimens and treatment options.
3. Obtain clinical specimens requested by the public health department and arrange to have them transported to a designated public health laboratory. These will probably consist of a nasopharyngeal swab, nasal swab, throat swab, and an acute serum specimen (for comparison to a convalescent specimen 2 to 3 weeks later).
4. Evaluate alternative diagnoses. Remember that a novel influenza infection can co-infect with a more common organism. Discontinue isolation and antiviral therapy prematurely only if an alternative diagnosis is confirmed with a high-predictive value test, the clinical course is explained by the alternative diagnosis, and the epidemiologic link to the novel influenza strain is not strong.
5. Start antiviral treatment.
6. Assist the public health department in locating potentially exposed contacts and providing antiviral prophylaxis if recommended.

Clinical guidelines: Pandemic period

During the pandemic period, managing suspected infection differs from the pandemic alert period in several respects.

1. Suspected cases need only meet the clinical criteria: fever with sore throat, cough, or dyspnea. These criteria may be modified as the pandemic evolves.
2. Hospitalize only those patients with severe complications who cannot be cared for at home.
3. Submit clinical specimens to the designated lab only as requested by the public health department. Such monitoring will probably be needed only for a subset of patients to watch the epidemiology of the epidemic or to investigate unusual presentations or failures of preventive therapy.
4. Report atypical cases, prophylaxis failures, and other abnormal cases to the public health department.

Pre-pandemic planning

If and when another influenza pandemic will occur is difficult to predict. To be prepared, follow sound public health practices: adhere to office infection control practices, insure that patients and staff are current on all immunizations—influenza and pneumococcal vaccines can probably limit the complications from a novel influenza pandemic—maintain a line of communication with the local public health department, report communicable diseases and suspicious presentations to the public health department, and participate in local emergency planning.

Family physicians who serve in leadership positions in hospitals and other health care facilities can also promote planning for a possible pandemic at these facilities, including how to manage a surge of critically ill patients.

CORRESPONDING AUTHOR
Doug Campos-Outcalt, MD, MPA, 4001 North Third Street #415, Phoenix, AZ 85012. E-mail: [email protected]