New York, Jan 30 (IANS): One-third of people in the US are either unlikely or at least hesitant to get a Covid-19 vaccine when it becomes available to them, a new study suggests.

The findings, published in the journal Vaccine, indicates that demographic characteristics, vaccine knowledge, perceived vulnerability to Covid-19, risk factors and politics likely contribute to vaccination hesitancy.

"Our research indicates that vaccine uptake will be suboptimal with 14.8 per cent of respondents being unlikely to get vaccinated and another 23 per cent unsure," said lead author Jeanette B. Ruiz, Assistant Professor at the University of California, Davis.

For the study, the research team recruited participants from the US through an Internet survey panel of 2.5 million residents developed by a commercial survey firm.

The team measured the respondents' intention to vaccinate; demographic and health status profile of individuals least likely to vaccinate; general vaccine knowledge and vaccine conspiracy beliefs; and the role of media and partisan politics played in their resistance to vaccination.

The respondents cited vaccine safety and effectiveness assessments as the primary basis for hesitancy.

Respondents relying primarily on social media for information about Covid-19 anticipated a lower likelihood of Covid-19 vaccine acceptance, the study found.

The top four reasons given for vaccination hesitancy were concerns about vaccine side effects, worries about allergic responses to the vaccine, doubts about vaccine effectiveness and a preference for developing immunity through infection.

Other reasons were less frequently cited -- including being healthy, fear of needles, being immune from past infection, being young and lack of concern about developing a serious illness.