Pulmonary Medicine Made Easy: Swine Flu

-Epidemiology: (Outbreaks in humans)

a. 1918 flu pandemic (Spanish) in humans was associated with H₁N₁ à infected 1/3 of the world's population (or around 500 million persons at that time) and caused around 50 million deaths.

b. 1976 U.S. military outbreak à less deaths due to early immunization (with few deaths due to vaccine caused Guillain-Barre syndrome).

c. 2009 U.S. outbreak à American cases were found to be made up of genetic elements from 4 different flu viruses "an unusually mongrelised mix of genetic sequences or antigenic shift or reassortment":

§ North American swine influenza,

§ North American avian influenza,

§ Human influenza, and

§ Swine influenza virus typically found in Asia and Europe (one theory mention involvement of Mexican infected pigs).

Agent, group		Treatment	Chemoprophylaxis
Oseltamivir
Adults		75-mg capsule twice per day for 5 days	75-mg capsule once per day for 10 days
Children ≥ 12 months	15 kg or less	60 mg per day divided into 2 doses	30 mg once per day
	16-23 kg	90 mg per day divided into 2 doses	45 mg once per day
	24-40 kg	120 mg per day divided into 2 doses	60 mg once per day
	>40 kg	150 mg per day divided into 2 doses	75 mg once per day
Children 6-11 months		25 mg twice daily	25 mg once daily
Children 3-5 months		20 mg twice daily	20 mg once daily
Children <3 months		12 mg once daily	Not recommended
Zanamivir
Adults		Two 5-mg inhalations (10 mg total) twice per day	Two 5-mg inhalations (10 mg total) once per day
Children		Two 5-mg inhalations (10 mg total) twice per day (age, 7 years or older)	Two 5-mg inhalations (10 mg total) once per day (age, 5 years or older)