AMA: Swine Flu

April 27, 2009 -- The Centers for Disease Control and Prevention (CDC) has confirmed that human cases of swine influenza A (H1N1) virus infection have been identified in the United States and internationally. Investigations are ongoing to determine the source of the infection and whether additional people have been infected with swine influenza viruses.

The CDC has prepared interim guidance on how to care for people who are sick as well as on the use of face masks in a community setting where the spread of this swine flu virus has occurred. For the most recent information concerning swine flu infection, please see the CDC Web site.

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The American Medical Association (AMA) will be following developments closely, and will be posting additional resources on this development as they become available.
About swine flu

Swine flu is a respiratory disease of pigs caused by a type A influenza virus that regularly causes outbreaks of influenza among pigs. Swine flu viruses do not normally infect humans; however, human infections with swine flu do occur. Public health officials have determined that this strain of swine flu virus spreads from human to human and can cause illness.

The outbreak is ongoing and additional cases are expected. The human symptoms of swine flu are similar to the symptoms of seasonal influenza and may include:

* Fever (greater than 100°F or 37.8°C)
* Sore throat
* Cough
* Stuffy nose
* Chills
* Headache and body aches
* Fatigue

Some people have reported diarrhea and vomiting associated with swine flu. Severe illness (pneumonia and respiratory failure) and deaths have been reported with swine flu infection in people. Like seasonal flu, swine flu may cause a worsening of underlying chronic medical conditions.

Infectious period
Persons with swine influenza A (H1N1) virus infection should be considered potentially contagious for up to seven days following illness onset. Persons who continue to be ill longer than seven days after illness onset should be considered potentially contagious until symptoms have resolved. Children, especially younger children, might potentially be contagious for longer periods.

Non-hospitalized ill persons who are a confirmed or suspected case of swine influenza A (H1N1) virus infection are recommended to stay at home (voluntary isolation) for at least the first seven days after illness onset except to seek medical care.
Specific guidance for clinicians

The CDC has drafted guidelines and resources for clinicians. The CDC recommends that clinicians consider the possibility of swine influenza virus infections in patients presenting with febrile respiratory illness. If swine flu is suspected, clinicians should obtain a respiratory swab for swine influenza testing and place it in a refrigerator (not a freezer). Once collected, the clinician should contact their state or local health department to facilitate transport and timely diagnosis at a state public health laboratory.

Laboratory testing has confirmed that the swine influenza A (H1N1) virus is susceptible to the prescription antiviral drugs oseltamivir and zanamivir and the CDC has issued interim guidance for the use of these drugs to treat and prevent infection with swine influenza viruses.

The following are interim guidelines from the CDC

Infection control of ill persons in a health care setting
Patients with suspected or confirmed case-status should be placed in a single-patient room with the door kept closed. If available, an airborne infection isolation room (AIIR) with negative pressure air handling with six to twelve air changes per hour can be used. Air can be exhausted directly outside or be recirculated after filtration by a high efficiency particulate air (HEPA) filter. For suctioning, bronchoscopy, or intubation, use a procedure room with negative pressure air handling.

The ill person should wear a surgical mask when outside of the patient room, and should be encouraged to wash hands frequently and follow respiratory hygiene practices. Cups and other utensils used by the ill person should be washed with soap and water before use by other persons. Routine cleaning and disinfection strategies used during influenza seasons can be applied to the environmental management of swine influenza. More information on environmental management.

Standard, Droplet and Contact precautions should be used for all patient care activities, and maintained for seven days after illness onset or until symptoms have resolved. Maintain adherence to hand hygiene by washing with soap and water or using hand sanitizer immediately after removing gloves and other equipment and after any contact with respiratory secretions.

Personnel providing care to or collecting clinical specimens from suspected or confirmed cases should wear disposable non-sterile gloves, gowns, and eye protection (e.g., goggles) to prevent conjunctival exposure.

Masks and respirators

Interim recommendations:

*
Personnel engaged in aerosol generating activities (e.g., collection of clinical specimens, endotracheal intubation, nebulizer treatment, bronchoscopy, and resuscitation involving emergency intubation or cardiac pulmonary resuscitation) for suspected or confirmed swine influenza A (H1N1) cases should wear a fit-tested disposable N95 respirator.*
*
Pending clarification of transmission patterns for this virus, personnel providing direct patient care for suspected or confirmed swine influenza A (H1N1) cases should wear a fit-tested disposable N95 respirator when entering the patient room.

*Respirator use should be in the context of a complete respiratory protection program in accordance with Occupational Safety and Health Administration (OSHA) regulations. Information on respiratory protection programs and fit test procedures can be accessed on the OSHA Web site. Staff should be medically cleared, fit-tested, and trained for respirator use, including: proper fit-testing and use of respirators, safe removal and disposal, and medical contraindications to respirator use.

Antiviral drug use

The swine influenza virus (H1N1) has thus far been susceptible to osteltamivir (Tamiflu) and zanamavir (Relenza), but not to amantadine or rimantidine. Antiviral doses and schedules recommended for treatment of influenza A (H1N1) are the same as those recommended for seasonal influenza.

* Treatment: The recommended treatment for a suspected or confirmed case of swine influenza (H1N1) is a five-day course of zanamavir or oseltamivir. As with human influenza, immunocompromised patients may require longer courses of therapy.
* Prophylaxis: The recommended prophylaxis for unprotected close contacts of confirmed or suspected cases is a seven-day course of zanamavir or oseltamivir at the prophylactic dose. Please contact the Infectious Diseases Consultation Service for advice on treatment or prophylaxis of patients. Please contact the Occupational Medical Service for advice on treatment or prophylaxis of staff.
* For Special populations (pregnancy) and additional CDC guidance on antiviral therapy:
Interim guidance on antiviral recommendations
Dosage table

Travel advisories

People entering the United States who are experiencing symptoms consistent with swine flu and have traveled to an affected area, or have been exposed to someone possibly infected with swine flu, during the last seven days should report their illnesses to their health care provider immediately and inform them of their recent travel. People traveling from the United States to affected areas should be aware of the risk of illness with swine flu and take precautions.

Source: AMA