COVID-19 <%ec%a7%88%eb%b3%91%ea%b4%80%eb%a6%ac%ec%84%bc%ed%84%b0 class="post-title"> U.S. CDC acknowledges airborne transmission of COVID-19 %ec%a7%88%eb%b3%91%ea%b4%80%eb%a6%ac%ec%84%bc%ed%84%b0> October 6, 2020