A new study has concluded that children with chronic illness, especially respiratory illness, are more likely to develop H1N1 influenza.

Children with chronic illness, especially respiratory illness, are more likely to develop H1N1 influenza that requires critical care and that the virus is likely to change course as it attacks the lungs throughout the course of the illness, said the H1N1 study focusing exclusively on critically ill children.

Senior author, David G. Nichols, MD, professor of anesthesiology/critical care medicine and pediatrics at the Johns Hopkins University School of Medicine, said," The good news is that all of our patients survived, even though some needed mechanical ventilators and heart medication."

H1N1 influenza appears to have increased infection rates among children and young adults and varies in severity as compared to seasonal influenza.

Cases of 13 critically ill children with H1N1 admitted to the Johns Hopkins Hospital Children's Center pediatric intensive care unit during the spring and summer of 2009 were reviewed by the researchers to reach the conclusion.

They found that the vast majority (92 percent) of the children had an underlying chronic disease, usually a lung disease such as asthma, before contracting H1N1 infection.

Dr. Nichols further explained," Critical H1N1 disease in children has different and rapidly changing manifestations in the patients' lungs. Some children behaved as though they were having an asthma attack, while other children behaved as though they had severe pneumonia. Some children had both or switched from one to the other. These variable and changing manifestations of lung infection made life support with a mechanical ventilator challenging and required us to constantly reassess and readjust treatments." (With Inputs from Agencies)