"The more widespread it is in the community, the more it can breakthrough to those vaccinated. For a few weeks, let's all take care, aim to see this off and reduce illness," he said.
Reid also said that younger age groups are the "new vulnerable groups" as they have yet to be vaccinated.
Speaking to Newstalk on Sunday, the HSE Chief asked younger cohorts to “mind themselves and protect themselves in the coming days and weeks" as Ireland's vaccine rollout continues to progress.
“They are the new vulnerable groups because they aren’t vaccinated,” he said.
