Nearly 750,000 vials of the popular human papillomavirus (HPV) vaccine Gardasil have been recalled over a fear of glass shards contained in the vials. Merck, the drug’s manufacturer, says there may be up to 10 vials with the glass remnants, although the company has since recalled an entire lot of the vaccine.

The Centers for Disease Control and Prevention (CDC) released a statement saying between Aug. 20 and Oct. 9, any shipments received by offices and clinics of lot number J007354 should be returned immediately. While administering the vaccine with glass particles, which can potentially fit inside a needle, does not reduce the vaccine’s effectiveness the CDC said people may experience redness and swelling around the injection site. To date, the agency hasn’t received reports of any adverse effects.

“We do not expect delayed side-effects to occur,” the report states. “If you or your child recently received HPV vaccination, there is no need to be revaccinated.”

HPV vaccination, much like other forms of vaccination, has received mixed opinions — many of the opponents cite anecdotal evidence of increased promiscuity among pre-teen daughters, severe side-effects of decreased egg formation, and links to other disorders, most popularly autism. However, many doctors reject the idea that vaccines do harm — the HPV vaccine in particular, as the virus currently stands as the leading cause of cervical cancer.

According to the CDC, some 79 million Americans currently live with HPV. The virus is so common, in fact, nearly all sexually active people will contract it at some point in their lives, the agency reports. Many never know they have the virus, as it may not show symptoms.

Despite the 743,360 vials involved in the lot, which Merck believes could contain glass as a result of a packaging break during the manufacturing process, the CDC said the vaccine itself won’t see any changes.

“Merck is contacting offices or clinics who received vaccine from lot J007354 and providing them with procedures to return any of the vaccine that has not been used,” the agency stated. “This voluntary recall does not affect the supply of vaccine. Clinicians’ offices who have administered this vaccine do not need to re-vaccinate anyone.”

The CDC maintains its recommendation that boys and girls receive three doses of the HPV vaccine by the time they reach 11 or 12 years of age.