RAMALLAH — The Palestinian Ministry of Health Sunday said that four Palestinians have died of swine flu in the West Bank and Gaza Strip in the last 24 hours, bringing the number of victims to 21 since the start of this winter. As'ad Al-Ramlawi, Director General of the Healthcare Department of the Palestinian Ministry of Health, said that three — two elderly men and a child — died of complications in the governorates of Ramallah, Al-Biereh and Hebron. Al-Ramlawi said that an elderly Palestinian man died in Gaza Strip, the first case in the coastal enclave since the start of winter. He pointed out that some 600 people have been diagnosed with swine flu, 30 of them in Gaza Strip. The official said that that most of the people who succumbed to the disease had weak immune systems or were suffering from pre-existing illnesses. The majority of people have gone to hospital and been treated for the virus, he said. Children, the elderly, patients with chronic illnesses, and pregnant women are considered to be at high risk of contracting the disease, he said. Al-Ramlawi said that his ministry said it has doubled its efforts to combat the virus and is equipped with all the necessary medicines and testing kits. Roughly 25,000 people have been vaccinated so far. Symptoms of swine flu include a fever, cough, headache, weakness and fatigue, aching muscles and joints, sore throat and a running nose. Swine flu, also called H1N1 flu, swine influenza and hog flu, is an infection caused by any one of the several types of swine influenza virus like H1N1, H1N2, H3N1, H3N2, and H2N3.