Parents who had their children vaccinated in the meningococcal B campaign - and others who did not - told researchers they were unable to get enough reliable information on it.
The Government spent more than $200 million on New Zealand's largest mass-vaccination campaign.
More than one million children and teenagers were injected between July 2004 and last December. The programme for those aged five to 19 has now virtually ceased, but the vaccine continues to be offered for infants.
A study published in today's New Zealand Medical Journal found that parents had a "largely unfulfilled desire for reliable, valid and balanced information about the MeNZB vaccine".
In the study by the Christchurch Polytechnic Institute of Technology and Christchurch Hospital, 21 parents were interviewed: 10 consented to their children being given the vaccine, 10 withheld consent and one chose to have just one of their two children vaccinated.
Senior nursing lecturer Paul Watson and colleagues say in the study that all the parents followed a similar decision-making process. It involved a gut reaction, a trigger point, a hunt for information and a balancing of the perceived risks of the disease versus the vaccine.
"Parents wanted accurate, balanced and referenced information from the Ministry of Health officials and health professionals, however, most reported dissatisfaction and mistrust with 'official' information received."
"Parents who consented to vaccinate, and those who declined, frequently described the ministry ... media publicity as 'scare-mongering', 'controlling people through fear', 'fear-driven', 'not balanced' and 'one-sided'."
Parents of school children were concerned about the graphic nature of information provided to children at school, mostly without consent. One consenting parent says in the study: "They came home from school having seen the promo, they actually sent a video around the schools, they showed it to children as part of the health programme unbeknownst to parents and they all came home within two days of each other, saying, 'Oh I've got to have this injection or we're going to get this horrible disease'. So, really, faced with the fear of the children, I felt like I didn't have a choice."
One parent reported being encouraged to give vaccine consent by the story of Charlotte Cleverley-Bisman, who, as a baby, caught meningococcal disease shortly before the campaign, became extremely sick and had limbs amputated.
But others were cynical, believing the intense media coverage of Charlotte and her father Perry's presence at public meetings to be a "deliberate ministry strategy designed to influence vaccine uptake".
* A separate study in the journal investigated hospitalisation rates for bronchiolitis before and after the campaign because, during a clinical trial of the vaccine, five participants under one who were given the vaccine, and one who was not, were hospitalised for the disease. Bronchiolitis is the commonest lower-respiratory-tract infection in children under one and is mostly caused by respiratory syncytial virus.
The researchers concluded the vaccine was not associated with an increased risk of hospitalisation for the disease.