( CNN ) -- Mary Peterson of Des Moines , Washington , does n't believe the vaccine for the novel H1N1 flu has been studied enough to get it for herself and her daughters , who are 1 and 3 years old . Mary Peterson 's daughters , 3 and 1 , will not be getting the new vaccine , she said . `` I wrestled with it , '' she said . `` I think the side of caution in this case is just waiting until we have more information . '' Peterson is one of many parents who are discussing -- whether in real life or on Twitter -- their skepticism of the vaccine . The vaccine is being distributed as an intranasal spray this week , and will arrive next week in injection form , said Dr. Thomas Frieden , director of the Centers for Disease Control and Prevention , earlier this week . The CDC and other public health authorities say the new vaccine is safe , and are encouraging everyone to get it , especially those in high risk groups . But experts acknowledge that many people struggle with the decision . Take a quiz about H1N1 flu » . `` I bet half the people in the country have concerns , '' Dr. Mehmet Oz , host of the `` Dr. Oz Show '' and professor of surgery at Columbia University , told CNN 's Anderson Cooper earlier this week . `` Be knowledgeable , though , that the H1N1 swine flu vaccine is built on a chassis of the older original seasonal vaccine . So , it should have similar risks , which have proven to be very low , '' he said . Priority groups for the vaccine include pregnant women , caregivers and household contacts of children younger than 6 months , people between the ages of 6 months and 24 years , and anyone ages 25 to 64 with existing health problems , according to the CDC . A recent survey from the Harvard School of Public Health found that just 40 percent of adults say they are `` absolutely certain '' they will get the H1N1 vaccine . An additional 41 percent said they `` will not get it , '' and the rest of the sample had various degrees of certainty . iReport.com : Are you getting the vaccine ? `` You 've got a significant group of people who at the moment would n't do it , '' said Robert Blendon , professor of health policy and political analysis at the Harvard School of Public Health , who led the study . Still , nearly 60 percent of those who say they do n't think they 'll get vaccinated would change their minds if there were sickness or death in their community , the study found . See H1N1 in your geographic area » . Moreover , 51 percent of parents said they were `` absolutely certain '' to get it for their children . Again , about 60 percent of the skeptical parents would change their mind in the event of community sickness and death . One major group of people who say they probably wo n't get the vaccine are those primarily concerned about safety , Blendon said . Peterson is n't against all vaccines -- she and her daughters have already gotten the seasonal flu vaccine , for example . But she is concerned about mercury in some of the new vaccine varieties . Thimerosal , a mercury preservative found in the multi-dose vial H1N1 vaccines , has been controversially linked to autism , though no studies have proved that theory . Peterson said she is also concerned about the toxicity of mercury . But the CDC says there is no evidence that thimerosal is harmful to pregnant women or fetuses . Vaccine companies are making vaccine types for both seasonal flu and H1N1 flu without this mercury-based preservative . The other main reason that people cite for not getting the vaccine is that they do not believe they are vulnerable to the disease , Blendon said . Crystal Fincher , who works in sales in Seattle , Washington , has both safety and vulnerability in mind . She has decided against vaccinating herself and her 12-year-old son both because she does n't believe there is enough safety information about it , and because she does n't think she and her son are in high-risk groups . Fincher said her son 's own physician told her the risks of combining the new H1N1 vaccine with his other scheduled vaccines -- for example , tetanus and diphtheria -- are not yet known . `` I just do n't feel like there 's a risk of having a complication from swine flu is high enough to proceed to taking that , but I would be open in the future once there was more data available , '' she said . Teresa Rogers , a pharmacy technician in Rockford , Michigan , said she will not be getting the swine flu vaccine because she believes it has not been tested enough . Her children , who are grown , will probably not get it either , and her co-workers at the pharmacy are split . `` I 'm not going to be a guinea pig , '' she said . But Karen Walrond , a photographer and writer in Houston , Texas , said she will vaccinate her 5-year-old daughter , whose asthma flares up as a result of colds and flus . `` We will probably go ahead and risk it , '' she said . Walrond herself will probably also get vaccinated , if only `` in moral support '' of her daughter , she said . Oz said he will get the vaccine , but his wife will not , and the kids will go along with her , as in most families . `` I think we 're going to have this battle within American families and within our culture . It should be a productive one , though , '' he said . `` It 's about getting the middle mass of Americans to say , 'You know what , this is what I think : I 'm going to go with the system and get the vaccine . ' ``
Dr. Oz : `` I bet Two the people in the country have concerns '' The Washington vaccine is made with the same process as the seasonal flu shot . Survey : just 40 percent of adults are `` absolutely certain '' they will get vaccine . half key issues for skeptics are the safety of vaccine and their own vulnerability .