While governments, international bodies and the public health community scramble to arrest the COVID-19 virus, now a pandemic, and with states of emergency declared nationwide and in Massachusetts, medical experts are still trying to come up with vaccines that can do a better job against various strains of influenza that have sickened and killed people for many decades.
The experts say the effectiveness rate of flu shots should be at least 90% successful.
But data collected for nearly two decades by the US Center for Disease Control and Prevention show effectiveness rates often hovers between 40 and 50%.
Data from the 2018-2019 flu season, the most recent set of complete information, first published in June, indicated that a flu shot to prevent influenza A, the H3N2 strain, was only 9% effective in preventing onset of the flu, among all age groups.
