Because the principal vector carrying Zika, the Aedes mosquito, is widespread in Vietnam, the country faces the risk of endemic transmission, a situation where infections occur year-round, a WHO spokesperson told CNBC on Wednesday.
The Zika fever, which has similar symptoms to dengue fever, is not typically regarded as life-threatening but it has resulted in deaths and is especially dangerous for pregnant women as it can cause birth defects. There is no known treatment, but global scientists are working on a number of vaccines and preventive treatments.
Last month, the virus entered Vietnam's rural areas, particularly the southern Dong Nai province, where local health authorities declared an outbreak within the Vinh Thanh commune on Jan. 9 after four new cases were reported from December to early January, local media said.
"Data collection and analysis should be enhanced to monitor the geographical distribution and temporal trends of Zika virus transmission and related complications, especially the congenital virus syndrome Guillain-Barre," the WHO said, adding that it was working closely with the government to strengthen the country's preparedness and response capacity.
Of course, it's not just Vietnam battling fresh outbursts this year.
Last month, Angola reported its first two cases of the disease, which come on the heels of a major yellow fever epidemic in the Southwest African nation. Stateside, Florida has announced four new incidents since the year began and one new contraction was reported in Texas last week. And last month, Jamaican authorities declared the country's first case of microcephaly, a condition where heads of newborn babies are smaller than average.
"Overall, the global risk assessment has not changed," the WHO said in a January report, warning that vigilance worldwide must remain high.