NEW YORK -LRB- CNN -RRB- -- Five new cases of the H1N1 virus in New York City schools will force three schools to close for a week , Mayor Michael Bloomberg said at a news conference Thursday evening . The city is temporarily closing the schools to `` slow transmission '' of the virus , Mayor Michael Bloomberg said . The two intermediate schools and one primary school are in Queens , and all three will be closed for at least five days , the mayor said . `` We are closing the schools to slow transmission '' of sickness , he said . Bloomberg , flanked by New York Gov. David Paterson and New York City School Chancellor Joel Klein , said four students at one of the intermediate schools have the virus and an administrator was critically ill Thursday with H1N1 . Bloomberg indicated the school administrator had a pre-existing medical condition . Fifty students at that school have been sent home with flu-like symptoms since May 6 . At the two other schools , the primary school had an overflowing nurse 's office Thursday , reporting 29 students suffering from flu-like symptoms . The other intermediate school had 241 students absent with illness Thursday . The New York City Department of Health and the Department of Education have been in nearly constant contact , said Jason Post , a spokesman from Bloomberg 's office . When there 's a spike in students absent from classes , the Department of Health is alerted . `` There 's always good communication , flu or no flu , '' Post said . `` But our senses have been sharp for a while now . '' The Health Department has seen a general increase in flu activity in Queens , officials said in a news release . While the symptoms of H1N1 flu seem to resemble those of seasonal flu , the H1N1 virus appears to spread more extensively , at least in schools , warranting closures to slow transmission in the community , the release said . Dr. Isaac Weisfuse , the deputy commissioner of the city 's Department of Hygiene and Mental Health , said although concern is legitimate , there 's no solid evidence that suggests the H1N1 flu -- also known as swine flu -- is more dangerous than the flu in general . `` The bottom line is if you 're sick , stay home , '' Weisfuse said . `` And do n't go back to school until you 're better for one whole day . '' In late April , St. Francis Prep , a high school in Queens , was closed because of a flu outbreak . Since then , the school reopened and the stricken students have recovered , according to the mayor 's office . `` As we have said from the outset of the appearance of H1N1 in our city last month , we will share with New Yorkers what we know and not speculate on what we do n't know , '' said Bloomberg in a statement . According to the World Health Organization and the Centers for Disease Control and Prevention , as of Thursday night 7,412 cases of H1N1 flu have been confirmed worldwide . The organizations said 63 deaths attributed to the virus have been confirmed worldwide . The CDC said 4,298 cases of the virus and three fatalities have been confirmed in the United States as of Thursday night . New York had 224 confirmed cases of H1N1 , the CDC said . It was not clear whether the five cases cited by Bloomberg and the other New York officials were included in the latest CDC total .