Both Nassau and Suffolk health departments said they had received some of the children's H1N1 flu vaccine doses that have been recalled because they lack potency.
"We know exactly where every single dose was sent and how much went to each provider," Nassau County health department spokeswoman Mary Ellen Laurain said. "We are reaching out to those providers."
Vaccine maker Sanofi Pasteur announced Tuesday it was recalling about 800,000 doses nationwide of pediatric H1N1 vaccine in prefilled syringes for children ages 6 months to 35 months. The company said it found the vaccine's potency in four different lots was below a specified limit.
Safety of the vaccine was not an issue, Sanofi and the U.S. Centers for Disease Control and Prevention said.
Children who received the less potent doses do not have to be revaccinated, the CDC said. Children under 10 need two doses anyway; if a child has received a second shot, he or she should have immunity, the CDC said.
Laurain said Nassau had received 2,660 doses in two of the four recalled lots and had distributed 2,230 doses.
Suffolk's acting health commissioner, Dr. Linda Mermelstein, said the county received 500 doses of the recalled vaccine.
The state Department of Health said it has identified 251 providers throughout the state, including county health departments, hospitals, clinics and private doctors, who had received vaccine from the recalled lots.
"We are contacting them to make them aware of the recall," said health department spokeswoman Claudia Hutton.
Len Lavenda, a spokesman for Sanofi Pasteur, said the company was halting further shipment of vaccine in single dose vials for this age group until the cause was identified.
This could present a potential problem for parents looking to vaccinate infants and young toddlers. Dr. Sharon Nachman, a pediatric infectious disease specialist at Stony Brook University Medical Center, said Sanofi Pasteur is "the most commonly used and one of only two products for vaccines in this age group."
Dr. Paul Lee, an infectious disease specialist in Mineola, said he believed most practices have run out of the Sanofi pre-filled syringes. "There are practitioners who may have some doses, but finding a Zu Zu pet now would probably be easier," he said.
There are other alternatives, including nasal spray vaccine and multidose vials, although nasal vaccine can be used only in children over age 2.