SINGAPORE - Thousands of older people around the world have begun receiving Covid-19 booster shots to further protect them against infection and severe illness - especially as immunity has been shown to wane over time. But should healthy young adults be next in line? While the jury is still out on that subject, some local scientists believe that the risks may currently outweigh the benefits. The topic came up during a webinar on Thursday (Sept 16) on living with Covid-19 during which three experts at the forefront of Singapore's Covid-19 fight shared their insights. The session was organised by The Straits Times and moderated by senior health correspondent Salma Khalik. Why boosters? In Singapore, only two groups of people are being offered booster shots for now: those aged 60 and above, and the immunocompromised. For those with weakened immune systems, the data is clear. As they tend to produce fewer antibodies than healthy people after vaccination, a third shot is recommended. The same logic applies to the elderly, who are also believed to have a lower immune response to the vaccine - although the scientific evidence for this proposition is less strong, said Professor Ooi Eng Eon...