Since February, Kathy Xiang and her entire family has been under siege.

Her 12-year-old daughter has had whooping cough, rhinovirus and parainfluenza: She's missed more than five weeks of school in total. Xiang, a software developer in Shanghai, caught all three too. Her elderly parents, who were helping care for her 10-month-old, tested positive for COVID-19 in early March, and her father got shingles.

Then the baby caught parainfluenza and pneumonia, necessitating five days on an IV drip. "I was literally numb after the baby boy got sick despite all our efforts to protect him,” Xiang said. "I was physically and mentally exhausted.”