090825) -- SAN JOSE, Aug. 25, 2009 -- Costa Rican President Oscar Arias (2nd L) is present at the opening ceremony of the Immunization Expert Conference held by the Pan American Health Organization in San Jose, Costa Rica, on Aug. 24, 2009. A group of 150 immunization specialists from Latin American countries met on Monday in Costa Rica to discuss vaccination strategies against the A/H1N1 flu, the Pan American Health Organization (PHO) said. Esteban Datos) (lmz