Originally Published: 14 JUL 21 13:08 ET

Updated: 14 JUL 21 14:47 ET

By Eric Levenson, CNN

(CNN) -- Mississippi State Health Officer Dr. Thomas Dobbs warned residents about a surge of Covid-19 cases in the southern state on Tuesday and said that seven children are in the state's ICUs, including two children on a ventilator.

"Please be safe and if you are 12 or older - please protect yourself," the doctor wrote.

The children make up a small fraction of the state's hospitalized patients. According to state data, there are 283 patients hospitalized with a confirmed Covid-19 infection as of Tuesday, including 98 in the ICU and 42 on ventilators. Hospitalizations have doubled since July 4, when there were 138 people hospitalized with confirmed Covid-19, according to the state data.

Despite the recent rise, Mississippi's hospitalization numbers are at about the same level as in May, and are down 80% from the peak in early January, when mass vaccination efforts had just begun.

In general, young people can become infected with Covid-19 and spread it to others but are far less likely to experience severe effects from the illness. According to the US Centers for Disease Control and Prevention, children under 18 account for 12.5% of US Covid-19 cases but just 0.1% of deaths, while people over 50 make up 95% of Covid-19 deaths.

Still, the upswing in cases among children and adults has caused renewed concern among public health officials as the Delta variant of Covid-19 spreads more widely.

Dr. Alan Jones, Associate Vice Chancellor for Clinical Affairs at the University of Mississippi Medical Center, said the hospital was seeing an increase in hospitalizations of children.

"We've had infants as small as 6 to 8 months old up to the teenage years. Many of them are not ICU-level patients and are just patients in the hospital on a regular floor, but we have seen an increase in both ICU patients as well as patients on the regular floor," he told CNN on Wednesday.

Many of these patients, he said, have a chronic comorbidity that makes them more likely to have a worse outcome from Covid-19. "But we also are seeing some that don't have any underlying medical conditions and are just a little bit more ill than they could stay at home for," he added.

Jones said most of these hospitalizations and deaths were preventable if more people get vaccinated.

"We're seeing a lot of respiratory illness now, both Covid and particularly RSV, respiratory syncytial virus, is going around heavily right now. I think that parents would like to have a situation where their children are as protected as they can be, but that requires everybody to do their part, wear masks when appropriate and get vaccinated," he said.

The rise in hospitalizations comes as Mississippi has the lowest vaccination rate in the US, with 44% of people 12 and up having received at least one vaccine dose, according to data from the CDC. Children under 12 are not yet eligible to be vaccinated against Covid-19 in the US.

Across the country, unvaccinated people make up the vast majority of cases, hospitalizations and deaths from the virus. Of Mississippi's 54 Covid-19 deaths between June 7 and July 5, just four were among fully vaccinated people, Dobbs said on Twitter.

Over the past week, states that have fully vaccinated more than half of their residents have reported an average Covid-19 case rate that is about a third of that in states which have fully vaccinated less than half of their residents, according to a CNN analysis of data from Johns Hopkins University and the CDC.

"We really need to get more people vaccinated, because that's the solution," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said Monday on "CBS This Morning." "This virus will, in fact, be protected against by the vaccine."