The US State of Hawai'i has approved the import of a live sample of the Zika virus as researchers step up efforts to find a vaccine.
An American Samoan woman who was infected with the virus is one of two people involved in a research project by the University of Hawai'i.
The university said the birth of two infants in Honolulu in December to mothers who were infected with the virus, including the American Samoan, illustrates how little is known about it.
Of the two babies, only one had microcephaly, a neurological disorder associated with unusually small heads and, often, brain damage.
The disorder is suspected to be linked to the Zika virus.
The World Health Organisation declared the Zika virus a global health emergency in February, after the virus spread through the Pacific and South America.
The university's Dr Vivek Nerurkar said there are many questions to be answered by the upcoming research.