East Riding of Yorkshire Council public health director Andy Kingdom said disruptions could last for a few weeks as outbreaks of infections lead to staff isolation and more patients hospitalized.
He added that he hoped high vaccine booster doses would reduce the number of people needing hospital treatment, but more time was needed to study trends.
It comes as 6,385 new cases of coronavirus were recorded in the East Riding from Tuesday, December 28 to Monday, January 3, up from 3,364 cases the week before.
The mobile infection rate fell from 980 to 1,860 cases per 100,000 people during the same period.
Mr Kingdom said the increases were even larger among younger age groups, with the rate of working-age adults rising from around 500 to around 2,500 per 100,000.
He added that the rate for school-aged children had increased five to six times over the same period.
Mr Kingdom said: “We have seen a massive increase in infections.
“The question at the moment is whether these new cases turn into hospitalizations or death?
“I’m watching this very closely, as the hope is that having both the shots and the booster will reduce the likelihood of this by about 85%. We already know that having vaccines reduces the risk of people ending up in the hospital, but the problem is, it doesn’t stop people from passing the coronavirus to each other.
“This has consequences that we are seeing with the staff not only in hospitals but in all the sectors that support them, it is the pressure that is on the system right now. I expect this wave of infections to be short and sharp, but it could do a lot of damage.
“And the problem is, because it takes about a month between catching the coronavirus and needing hospital treatment in the worst cases, we won’t see the impact of the New Year’s increases until the end of January.
“There is also the problem of the scale of infections, if we get 1,000 new cases a day, even if only 2% of people get seriously ill, it will increase the number of hospital patients.
“The NHS has already been under pressure this winter and every coronavirus patient taking a bed is one less bed that can be given to someone coming to A&E for example.
“If someone becomes ill with the coronavirus, the ambulance that takes them to the hospital cannot be used to pick up someone who has just had a stroke or a fall.
“If you are not vaccinated now, the chances of you not catching the coronavirus are very slim due to the number of people around you who have it.
“And now it’s too late for preventative measures like a lockdown, because infections are already in households, it’s more about minimizing the damage at this point.
“The good news is that Omicron’s reign should be short because so many people are infected that the population will develop a level of immunity.
“And I’m confident that we have the vaccines in the right people here, I don’t think we’ll see the number of hospitalizations and deaths we’ve seen elsewhere like London.
“But that’s only the case for those who are vaccinated, I think some people haven’t because they don’t think Omicron is that dangerous.
“But it does, if you don’t get the vaccine and catch it you’ll get really sick, and Omicron probably accounts for up to 99% of new cases now.
“If you could go to intensive care units in hospitals, you would see beds full of unvaccinated people.
“We hear stories from them saying, ‘if I only knew’, but by then it’s too late.
“We hope the outbreak of infections doesn’t overlap too much with staff absences and public health and other agencies have been planning this since before Christmas.
“But people shouldn’t expect that they would normally be waiting for health services in the next few weeks, there is going to be disruption.”