If you think COVID-19 won't affect you, think again.

Yesterday, there were 20 new coronavirus cases in NSW - the state's largest daily number of cases in three months.

Those new cases took the state's total to 3399, with 96 people being treated by NSW Health. Two people were in intensive care, one of whom required a ventilator.

The insidious nature of coronavirus was reiterated by the state's chief health officer Kerry Chant yesterday, when she revealed a person in their 30s was in intensive care.

"I think it's always important to highlight that because often we tend to say this disease affects the elderly," Dr Chant said.

"And it does, on average, but there still will be young people that are impacted and it is a call out to everyone to take this COVID-19 very seriously."

Dr Chant said while often the focus is on the severe effects of the disease on the elderly, "it is a numbers game".

"If young people are infected with COVID, a small number of them will actually have severe outcomes," she said.

"We have great clinicians and generally they have a good prognosis, but I think it is a warning that even young people can end up in intensive care with COVID-19."

Yesterday, NSW Premier Gladys Berejiklian said the next few weeks were "critical" for controlling the spread of coronavirus.

For many people, the yoyo-ing nature of the restrictions and the uncertainty around what the coming weeks and months look like are becoming too much. From Friday, restrictions will be tightened further in NSW.

"I don't want us to go down a track where we see suddenly a doubling or tripling of cases," Ms Berejiklian said yesterday.

"But we do have the chance to really get ahead of the virus, to control its spread, if all of us take those extra steps in the next few weeks."

Ms Berejiklian has urged people to go "above and beyond" the extra measures that come into effect on Friday - to "consider their actions, consider their movements in the next few weeks, given how tenuous the situation is in NSW".

For now, the rollercoaster ride of restrictions continues and, as the premier bluntly put it, we all have to live with COVID-19 until there's a vaccine.

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