By Anthony Boadle

BRASILIA (Reuters) - Brazil complained on Thursday that Venezuela was doing nothing to stop the spread of an outbreak of measles in Brazil and other neighboring countries that has been sparked by an exodus of Venezuelans fleeing economic collapse.

Since February, four people - three of them Venezuelan - have died of measles in the remote Brazilian border state of Roraima where health authorities have confirmed 281 cases of the disease, mostly among children.

The outbreak has prompted the Brazilian government to launch a nationwide campaign to vaccinate 11 million children, plus adults who request it. Although many Brazilian children are already vaccinated against the disease, the vaccination rate has dropped since Brazil was declared free of measles in 2016.

Brazil's Health Minister Gilberto Occhi said Venezuela had ignored Brazilian offers of assistance and vaccines and had not replied to requests for information to assess the extent of the epidemic.

"We need to know what Venezuela's policy is and what it has done to vaccinate its population, and so do other countries," Occhi said in a conference call with foreign media.

The Venezuelan Information Ministry did not immediately reply to a request for comment.

Occhi said Brazil was considering vaccinating all Venezuelans entering the country - some 2,000 people a day, with around half of those in transit or on a short-term visit. Currently only those that ask to stay as refugees or residents are vaccinated.

Brazil, along with Colombia and other neighbors, has been discussing the need for Venezuela to provide up-to-date information with the Pan American Health Organization (PAHO), an official said.

"All we have is preliminary data from 2017. They are not updating the information and we can't see the magnitude of the problem," said Carla Domingues, head of Brazil's immunization program.

PAHO said last month that nearly 2,500 confirmed cases of measles had been reported in the Americas in 2018, with over 1,600 of those occurring in Venezuela and nearly 700 in Brazil.

Since Venezuelans fleeing economic and political turmoil started entering Roraima at the only land crossing three years ago, Brazil has vaccinated 45,000 arrivals.

A decree by Roraima state government ordering the compulsory blanket vaccination of Venezuelans was struck down by the Supreme Court this week.

Measles vaccination in Brazil fell to around 70 percent coverage in 2017, a ministry official said.

(Reporting by Anthony Boadle, Additional reporting by Brian Ellsworth in Caracas, Editing by Rosalba O'Brien)