Jakarta, Indonesia ? Parents and children lined up Tuesday across Indonesia in a polio vaccination drive targeting 24 million youngsters, but health workers said some could be missed amid unfounded fears the vaccine is unsafe or violates Islamic law.

Polio has sickened 225 children since the virus reappeared in mostly Muslim Indonesia in March for the first time in 10 years. Tuesday’s operation was the latest effort in a six-month campaign to stamp it out.

“The preparation was good and certainly at this stage, there are encourage signs that the first national immunization day was a success,” UNICEF’s David Hipgrave said.

Scattered reports from Jakarta showed that turnout was high but Hipgrave said the actual level of participation nationwide won’t be known for days.

The country’s two largest Muslim organization endorsed the campaign and busloads of celebrities and politicians were sent out to convince a skeptical public that the vaccinations are safe. Rumors have spread that vaccinations led to the death of four children and violate Islamic law, similar to whisperings that spread through Nigeria during a polio outbreak there in 2003.

But some mothers said they had no plans to immunize their toddlers and officials with the U.N. children’s agency said they were afraid more parents would be dissuaded by a TV report and some health workers who wrongly said sick children could not be vaccinated.