RIO DE JANEIRO, June 13 (Xinhua) -- Flu has claimed at least 446 lives in Brazil so far this year, more than twice the figure of the same period in 2017, Brazil's Health Ministry said on Wednesday.

This year's overall flu cases stood at 2,700, according to the ministry.

The rise in flu deaths coincided with a lower-than-expected vaccination coverage in the country, despite health authorities' warnings.

The government has launched a vaccination campaign in April to immunize 54.4 million people against influenza. The main targeting groups included children, the elderly, pregnant women and indigenous populations.

The ministry said only 42.6 million people had been vaccinated.

"Our strategy today is to focus especially on children under five, in daycare centers and schools," said Brazil's Health Minister Gilberto Occhi, adding that efforts would be made to increase vaccination in the targeting groups.

Health officials are concerned as the winter season approaches, a time when flu cases usually peak.