Chikungunya virus (CHIKV) has been detected in humans in the Caribbean area for the first time in November 2013 (St-Martin Island). By February 2014, the virus had spread to several other Caribbean islands as well as French Guyana, South America. During the outbreak of Chikungunya that affected the Reunion island in 2005/2006, it was observed that the neonatal forms of infections acquired by mother to child transmission during childbirth, were not the exception and were critical. Mother-to-child transmission occurs when the mother is viremic at the time of delivery. The mean duration of viremia after the onset of first clinical symptoms is six days. The rate of mother-to-child transmission is 50%. All neonates contaminated during labor and delivery present with a symptomatic disease and the rate of severe forms is about 50%, primarily due to damage of the central nervous system, often leaving permanent damage (seizures, cerebral palsy).Due to the severity of Chikungunya in neonates and the burden of cerebral palsy, it is imperative to identify a safe and effective preventive and/or curative intervention. Human polyvalent immunoglobulins purified from plasma samples obtained from Chikungunya-convalescent donors exhibit a potent neutralizing activity in vitro. They were evaluated for their preventive and curative effects in a neonatal mouse model of CHIKV infection. After administration of a lethal dose of CHIKV, all neonatal mice that had received immunoglobulins survived while all control animals that had received non hyperimmune immunoglobulins died. In humans, specific human immunoglobulins proved to be effective and safe in neonates born to hepatitis B viremic mothers.