Puerto Rico's influenza cases could climb to epidemic levels this winter, Dr. Iris Cardona warned, pointing to the December-February respiratory season as the period of greatest risk. ^[1] The vaccine has been available on the island since August. So far 300,000 residents have received it, according to Cardona. ^[2] Weekly cases have already pushed past 3,000 ^[3], though the island remains below the epidemic threshold ^[4]. The season tally counts 13,696 cases ^[5], 990 hospitalizations ^[6] and 29 deaths ^[7], with 2,695 new cases in the most recent reported week ^[8]. None of the 29 dead had a registered influenza vaccination ^[9]. Last season, influenza did reach epidemic levels on the island ^[10]. Vaccination cuts the risk of severe complications by up to 80% ^[11], and pregnant women face 4 to 6 times the hospitalization risk of non-pregnant women ^[12]. December, January and February bring the highest respiratory-infection counts ^[13].