There isn't enough 'data' yet to do a complete analysis of people infected and sort them into groups. However, based on the pattern of the spread of the infection, and it's similarity with Influenza, the Center for Disease Control and Prevention has identified the following high risk groups.

Children: Children, especially those below the age of five are at a higher risk of contracting the H1N1 virus. Since children are not mature enough to understand the causes, they would not be sanitizing their hands frequently. Children with an existing medical condition, like immunosuppression, heart disease, sickle-cell anemia, diabetes, asthma or lung problems, fall in the highest risk category. Another high risk group among children is infants - those less than a year old.

Pregnant Women: The susceptibility of pregnant women to previous pandemics, especially influenza, puts them in the high-risk group. If affected, H1N1 patients have a high risk of preterm birth and spontaneous abortion. Since pregnant women may experience fetal distress related to maternal illness, it is recommended that they are tested in case of any symptom of the flu.

New Mothers: Infants get their antibodies - proteins produced by the blood to fight virus, bacteria, and other foreign infections - from breast milk. It is recommended that mothers start breast-feeding the babies soon after delivery. There is a high possibility of infection spreading from the baby to the mother, if the infant contracts the H1N1 virus. If the mother is infected with the virus after childbirth, she may still feed the infant after taking necessary precautions.

HIV Patients: HIV is a virus that destroys cells of the immune system. Patients with HIV are very prone to all kinds of infection, including swine flu. Those patients with lower CD4 counts need to exercise extreme caution during a pandemic. A low CD4 count means lesser strength of the immunity system, thus the extra precaution.

Older people and those that are morbidly obese have been found to be severely affected by swine flu. Though old age and obesity are not causes, since these groups usually have respiratory or breathing trouble, they are found to suffer from the flu more severely. In addition to the above-mentioned groups, people with heart, kidney, and liver problems have also been prone to infection from the H1N1 virus.

Needless to say, consult a physician when you suspect an infection.