This comes at the start of a second week of mass vaccination on the biggest island, Savaii, where people go to hospitals for the immunisation shots.
The Director General of Health, Leausa Dr Take Naseri, said a second private clinic which provided vaccination had done so after being approved by the previous National Health Services.
He said that clinic was not part of the investigation but was awaiting re-evaluation by UNICEF and the Ministry of Health to restart administration of measles vaccination.