As polar vortexes, nor'easters and monsoons ensue across the country, people are more likely to stay indoors, which also means that germs can circulate more easily.
원문출처 : http://www.cnn.com/2017/02/06/health/foods-boost-immune-system-diet-partner/index.html
원문출처 : http://www.cnn.com/2017/02/06/health/foods-boost-immune-system-diet-partner/index.html