Puerto Rico's influenza season is climbing toward its historical winter peak, and health officials used back-to-back briefings this week to press residents to get vaccinated now. Dr. Iris Cardona warned that weekly cases have pushed past 3,000, up from roughly 2,800 to 2,900 in recent weeks - on top of the 15,254 cases and 165 school outbreaks already accumulated between June and October.

The numbers still sit below the epidemic alert threshold, and officials are treating that as the window to act. Edna López, first vice president of the AFCPR, called vaccination a preventive measure that reduces infection risk and severity precisely because the island has not yet crossed that line, and stressed that it must be renewed every year, since the virus mutates and immunity fades. Cardona said December, January and February typically bring a considerable rise in respiratory infections, and that influenza reached epidemic levels in Puerto Rico last season.

The burden is already concentrated at the edges of age and health. Children aged 0 to 4 recorded 2,018 cases, the most of any age group, and pregnant women face four to six times the usual risk of hospitalization from influenza complications - one pregnant woman has died this season. Adults over 65 and people with chronic illness remain the other vulnerable groups. The starkest figure: none of the 29 people who died from influenza this season had a recorded flu vaccination.

About 300,000 Puerto Ricans have been vaccinated since doses became available in August - 288,254 people, roughly 9 percent of the population, as of the end of October. The vaccine cuts infection risk by about 50 percent, which is why officials keep repeating the same advice with the peak months ahead.