"Towards the end of December … we had a very bad situation in the UK and we still do. Firstly, because of the increased transmissibility of the new variant and the very high rise in the number of cases. At the same time, we're in a situation where, although the vaccine campaign or programme is being rolled out, we are still limited by the vaccine supply that we have. And so there is a constraint on how many vaccine doses are available", Lim told a parliamentary committee meeting.
Earlier on Wednesday, UK Health Secretary Matt Hancock told the Sky News broadcaster that the country's vaccine rollout programme was on track and reiterated the government's commitment to offering a first vaccine dose to everyone in JCVI's top four priority groups by 15 February.
Carehome residents and workers, frontline health care professionals, vulnerable individuals, and people over 70s are included in the JCVI's top four priority groups.
According to data published by the UK's Department of Health and Social Care, 2.4 million people have received at least one vaccine dose since the launch of the campaign.
On Tuesday, public health officials in the UK reported 45,533 new positive tests for COVID-19, a slight decrease from the 46,169 new cases registered on a preceding day.