This is likely to mean immunity levels decline and raises the risk of reinfection, researchers say.
The BBC presenter says she will break Covid rules so her family of seven can celebrate Christmas.
Kim Kyeong Yeon developed his virus-destroying machine after his child injured herself.
A new mural in east London is four storeys high, created with more than 200 flowers.
Joe Anderson spoke to BBC Breakfast’s Louise Minchin after his eldest brother’s death in October.
