A most arduous task for virologists is the annual "guessing game" of predicting what form the next wave of flu will manifest, so that enough preventive vaccines for the forecasted virus can be made available in a timely fashion to the elderly and vulnerable.
年復一年，為了「猜中」下一波流感會是哪些種組合，以便及時提供老弱民眾足夠的、可以預防該病毒的疫苗，遂成為全球病毒專家的最嚴峻考驗。