MANILA, Philippines (AP) — Philippine health officials say the deaths of three children inoculated with a Sanofi Pasteur dengue vaccine may have "causal association" to the inoculation and two of the children may have died because the vaccine failed.

The Philippines halted its immunization drive in December after Sanofi said a study showed the vaccine may increase the risks of dengue in people vaccinated prior to infection.

Health Secretary Francisco Duque III's office said Friday further study was needed on whether the vaccine that aimed to shield children instead infected them. Investigators found no evidence the rest of the 14 reported child deaths were related to the dengue vaccine.

Duque's office says the investigation result on the three deaths will be submitted to the Department of Justice, which is looking into possible criminal liabilities.