Vaccine: Indications: Injectable influenza vaccine should be considered for all pregnant women. The vaccine should be administered between mid-October and mid-November. Although not a common practice in the ED, any screening program for flu vaccine should put pregnant patients in highest priority group.

Nasal Spray Vaccine: Pregnant women should not receive the live nasal spray influenza vaccine, but family and household members and other close contacts of pregnant women (including healthcare personnel) who are 2 through 49 years old, healthy, and not pregnant may receive live nasal spray vaccine.

Contraindications: Same as in non-pregnancy. Pregnant women should not receive the live nasal spray influenza vaccine

Acute Infection: Clinical presentation is similar to the non-pregnant patient. Symptoms are usually self-limited, but complications should be anticipated if symptoms continue for longer than 5 days or if worsening clinical course. Influenza is usually a self limited infection, causing malaise, myalgias, fever, rhinorrhea, nausea, vomiting, cough, headaches, pharyngitis. Symptoms usually resolve within one week, though cough and malaise can persist beyond two weeks. The most common complication of influenza is pneumonia. Superimposed or secondary bacterial pneumonia develops two to fourteen days after influenza symptoms have resolved.

Testing : IIdeally, pregnant women who have suspected influenza infection should be tested for influenza. However treatment should be initiated based on clinical suspicion during influenza season. Reasons to avoid withholding treatment:

• significant rate of false negative rapid screens
• antivirals most effective within first 2 days of illness and still effective up to 4 days (see below).

Antiviral: As stated above, initiate treatment based on symptoms and local epidemiology. Also note that because influenza vaccination is not 100% effective in preventing influenza, a history of influenza vaccination does not rule out the possibility of influenza virus infection in an ill

patient with clinical signs and symptoms compatible with influenza.

Although zanamivir can be used in pregnancy, oseltamivir is preferred for treatment of pregnant women because of its systemic absorption. Theoretically, higher systemic absorption might suppress influenza viral loads more effectively in sites other than the respiratory system (e.g., placenta) and might provide better protection against mother-child transmission.

The drug of choice for chemoprophylaxis is less clear. Zanamivir may be preferable because of its limited systemic absorption; however, respiratory complications that may be associated with zanamivir because of its inhaled route of administration need to be considered, especially in women at risk for respiratory problems. For suspected influenza, oseltamivir treatment should be initiated as soon as possible – ideally within 48 hours of onset of symptoms. In addition, any pregnant woman hospitalized with confirmed, probable, or suspected infection should receive oseltamivir, even if more than 48 hours have elapsed since illness onset. Beginning treatment as early as possible is critical.