Aug. 25, 2009 -- Less than half of health care workers surveyed in Hong Kong intend to get vaccinated against swine flu, citing uncertainty about its effectiveness and possible side effects, a new study indicates.
And another new study shows that health care workers and some people in the general public may refuse to get immunized or vaccinate their kids, fearing that risks of a novel vaccine could outweigh benefits.
Researchers of both scientific studies say vaccination is critical, one of the most important ways to reduce illness and prevent death associated with pandemic flu complications.
The Hong Kong study is published by BMJ. The other study, based on analysis of 85 participants of focus group discussions in Canada, is published in Emerging Health Threats Journal.
Authors of the Hong Kong study describe their findings as surprising, given the fact that SARS (severe acute respiratory syndrome) had such a huge impact in Hong Kong, and note their information was gathered at the same time as the World Health Organization escalated its alert for swine flu to phase 5.
The SARS virus outbreak of 2003 infected more than 8,000 people worldwide and caused nearly 800 deaths.
Flu and Health Care Workers
Josette Chor, BSc, PhD of the Chinese University of Hong Kong, and colleagues of the BMJ study say that campaigns are needed to encourage vaccination of health professionals. The researchers gathered survey data from 2,255 health care workers at 31 hospitals. They were first surveyed about willingness to get a pre-pandemic vaccine against avian flu (H5N1) when the WHO influenza pandemic alert level was at phase 3 in early 2009. In May when the level had been raised to 5, they were asked about willingness to get a vaccine against the new H1N1 swine flu.
In the first survey, 28% of respondents said they’d be willing to get vaccinated for pandemic flu. The authors say “no significant changes in the level of intention to accept pre-pandemic H5N1 vaccine were observed,” despite the escalation to phase 5 of the swine flu pandemic.
About 48% of respondents said they’d take the shots against swine flu at phase 5, but many still said they worried about side effects of vaccines and efficacy.
“To our knowledge, this is the largest study conducted to assess the willingness of healthcare workers to accept pre-pandemic influenza vaccination, and it provides important information on barriers to vaccination,” the authors write.
Concerns Over Vaccine Safety
For the Canadian study, Natalie Henrich, PhD, MPH, of the University of British Columbia and doctoral student Bev Holmes at Simon Fraser University studied 85 people in 11 focus groups in Vancouver in 2006-2007. Participants in the Vancouver focus groups included university students, adult Canadians, parents, and health care workers.
They found that participants seemed reluctant to get a new vaccine during a pandemic "because of low perception of risk of infection early in a pandemic coupled with the many uncertainties that surround new vaccines and the emerging infectious disease." They note that "very few" said that they "would definitely get vaccinated."
Also, “participants were very concerned that in a pandemic, a vaccine would be brought to market without sufficient testing for safety,” the researchers write. Many felt that hand-washing and social distancing could help prevent disease.
But Henrich and Holmes say such steps, though worthwhile, aren’t enough, and that the message that vaccination is important needs to be broadly stressed.
In an accompanying BMJ editorial to the Chor study, Rachel Jordan, PhD, MPH, from the University of Birmingham, and Andrew Hayward, PhD, of the UCL Centre for Infectious Disease Epidemiology, say the first batch of H1N1 vaccine should be ready by October. They say it’s important for health workers to get the vaccine for personal and patient protection and also to reduce absenteeism.
The Hong Kong researchers say more study is needed to determine the root cause of the low intention to get vaccinated.