MAGGIE FICK WHEN Edith Serem received her COVID-19 vaccination last month at a hospital in Nairobi where she works as a doctor, nurses jokingly warned she might start speaking in a foreign language. Serem said some colleagues got the AstraZeneca shot after watching her closely for several days to see if she was okay, but others refused, still wary of possible side effects. Health experts worry that public scepticism about taking the relatively small number of doses African countries have battled to procure could prolong a pandemic that has already killed more than 3.3 million people worldwide. "I'm not an…