Recent laboratory analyses have identified Zika virus infections in three people who died in Brazil last year, the health ministry says, although authorities could not confirm that Zika alone was responsible for their deaths.
Brazilian Health Minister Marcelo Castro on Thursday confirmed the findings at a press conference, while announcing that a new partnership with scientists at the University of Texas could lead to laboratory development of a vaccine within a year.
He cautioned that full-fledged availability of a vaccine against the mosquito-borne virus would take longer.
The developments are the latest in an ongoing struggle with Zika in Brazil, which is at the centre of an outbreak that has spread to more than 30 countries and has prompted the World Health Organization to declare a global emergency over possible links between the virus and birth defects.
The ministry said Brazilian researchers found the virus in the body of a 20-year-old woman in the northeastern state of Rio Grande do Norte, who died last April from respiratory problems.
Two other patients last year also died from complications while they were infected with the virus.
Castro said the deaths possibly illustrated "comorbidity" caused by the virus and complications it may have caused in the patients.
The woman's respiratory problems were likely "associated with the infection," he said.
Only one in five people infected with Zika experience illness and even then they are normally mild symptoms. The virus is still poorly understood by scientists.
The government believes that as many as 1.5 million Brazilians may have been infected by Zika so far.
Scientists are investigating a potential link between infections of pregnant women and more than 4000 suspected cases in Brazil of microcephaly, a condition marked by abnormally small head size that can result in developmental problems.
Though laboratory tests have showed traces of Zika in patients affected by the believed complications, no proof yet exists to show it causes the birth deformations or any reported deaths.
