GENEVA • About 40 potential vaccines for the Zika virus are being tested, but none is likely to be available for women of childbearing age before 2020, the World Health Organisation (WHO) said.
WHO director Margaret Chan said the virus, linked to deformities in babies' heads and brains, remained "firmly entrenched" in large parts of the world.
Although progress towards prevention has been made with some drugs now undergoing clinical trials, "a vaccine judged safe enough for use in women of childbearing age may not be fully licensed before 2020", said Dr Chan.
The WHO declared in November that Zika was no longer a public health emergency.
However, Dr Chan said on Wednesday that the agency was setting up a new support programme for countries around the world.
The outbreak, which emerged in Brazil in 2015, has affected some 70 countries.
Zika, spread by infected mosquitoes and through sexual contact, causes only mild symptoms in most people.
However, pregnant women with the virus risk giving birth to babies with microcephaly, a crippling deformation that leads to abnormally small brains and heads. Zika has also raised alarm over its ability to cause Guillain-Barre syndrome.
In June last year, the WHO said that US$122 million (S$158 million) was needed to fund an 18-month plan to fight infections in women of childbearing age.
Meanwhile, Brazil and Latin America have recorded lower numbers of Zika infections this year compared with last year. But the WHO said all countries must remain vigilant against the virus.
"The prevalence of Zika is dropping, certainly in the Americas," Dr Ian Clarke, WHO incident manager for Zika, told a news briefing. But he said it is not clear why infection rates are falling.
"The anticipation was that we would see a second wave, certainly in Brazil and we haven't seen it. And we don't believe this is because we're not looking. There's a lot of surveillance ongoing," said Dr Clarke.
To date, 29 countries have reported thousands of babies born with Zika-linked microcephaly.
Angola last month said that it had recorded its first two cases of Zika.
In Singapore, the Ministry of Health said that as of Dec 27, 17 pregnant women were known to have had Zika. Four of them have given birth, and their babies show no signs of microcephaly.
Meanwhile, the National Environment Agency website showed that one case of Zika in the general population was reported last month.
AGENCE FRANCE-PRESSE, REUTERS