WHO recommended composition of influenza virus vaccines for use
:: WHO position paper on influenza vaccines - November 2012 published in Weekly Epidemiological Record (WER) (en inglés y francés)
Regional Office for the Americas of the World Health Organization 525 Twenty-third Street, N.W., Washington, D.C. 20037, United States of America Tel.: +1 (202) 974-3000 Fax: +1 (202) 974-3663