2017-18 Flu Season: What Have We Learned So Far?

On Feb. 2, 2018, Punxsutawney Phil, the world’s most celebrated weather forecaster, apparently “saw his shadow,” indicating six more weeks of frigid winter. At my home as of this writing, the temperatures are hovering in the low 50s and the flower buds are sprouting at the local park. The mangy marmot’s prognostications skills are “under further review.” Maybe, he meant six more weeks of flu season. If so, according to the Centers for Disease Control and Prevention’s most recent reports, his forecast would have been quite accurate. The worst flu season in almost a decade continues to ravage the U.S. Most states have been experiencing high levels of influenza-like illnesses, according to the CDC. Many of us have unfortunately suffered a respiratory illness or know someone who has. Those symptoms may have been influenza or other respiratory viruses. Even more worrisome, the hospitalization rate is the highest the CDC has ever recorded at this point in an influenza season. That rate has now surpassed that of the lethal 2014-2015 season, during which 710,000 were hospitalized and 56,000 died. Although the CDC does not keep exact counts of adult flu deaths, the report indicates nearly 10 percent of all deaths in the country during mid-February were due to influenza and related pneumonia. Flu hospitalization rates among adults over age 50 remained high. Media attention around this year’s influenza season has been particularly high. That focus has highlighted the tragic deaths of children related to influenza. Our local community has grieved the loss of a precious child. Adults who get a flu shot are 36 percent less likely to the disease, while for children, the figure was unexpectedly high at 59 percent. Regrettably, 80 percent of children who die related to flu are NOT vaccinated. At least four different strains of influenza are circulating now: two influenza A viruses — H3N2 and H1N1; in addition to two variants of influenza B. As of the first of February, about 74 percent of all flu samples genetically sequenced have been H3N2. This strain seems to account for influenza’s severity this year. More B strains are recently being detected. The last several months have been particularly harsh due to H3N2, which is associated with more complications, hospitalizations and deaths, especially among children, those older than 65 and people with certain chronic medical conditions. What have we learned? Flu season is not over. This influenza season started early and has remained intense. Outpatient visits for influenza-like illness decreased ever so slightly in the second half of February. This may be an early indicator that flu season may be near its peak. Yet, the other three strains of flu virus are proliferating. Don’t give up on the flu vaccine. The influenza vaccine needs some help with its image. We know the influenza vaccine is not perfect. It’s never as good as we wish it were. Although the headlines scream “ONLY 25 percent effective against the dominant strain H3N2,” according to the CDC that is more effective than expected. It is more effective against H1N1 and the B strains. The bigger surprise, the vaccine is almost 60 percent effective in children. Remember the children. For those children vaccinated, most recover from influenza without serious consequences. Parents must be alert to the signs of severe disease, such as respiratory distress, lethargy or signs of dehydration, which demand emergent evaluation. As noted, about 80 percent of children who die related to flu had NOT been vaccinated. Influenza vaccine remains our best means of prevention, and it is still not too late to get the influenza vaccine. Let’s hope the groundhog is as bad at predicting flu season as he is the weather. C. Clark Milton, D.O., is a fellow of the American College of Osteopathic Internists and the medical director of Corporate Health at Wheeling Hospital.