In response to the feedback from our first podcast in December, we have produced a follow-up interview with Professor Ben Cowling, the division head of the department of epidemiology and biostatistics in the School of Public Health at the University of Hong Kong. In this podcast, we discuss the expectations of the fourth wave in Hong Kong, the evolving new viral mutations and the outlook for immunization. Professor Cowling expressed his concerns about the early reports of the effectiveness of one of the vaccines currently proposed for Hong Kong.