SAO PAULO — The World Health Organization announced Tuesday that it now considers all of Sao Paulo state at risk for yellow fever, recommending that all international visitors to the state be vaccinated.

That puts the megacity of Sao Paulo on the list. But Brazil’s Health Ministry said in a statement that it was not changing its own, recently updated map of at-risk areas, which includes only certain parts of the state and city. The ministry said that the WHO’s more-cautious recommendation for foreigners was made in light of the fact that it is impossible to know where visitors might travel once they arrive in Sao Paulo state. Antonio Nardi, a senior official at the ministry, later told reporters it was the result of an “excess of concern.”

The announcement comes as an outbreak is gathering steam in Brazil during the Southern Hemisphere summer rainy season and just weeks ahead of Carnival, a major draw for foreign tourists. Nardi noted that most Carnival activities happen in cities, not in the forested areas that are of most concern, and so visitors should be safe.