At least 37 people were arrested in east China’s Shandong Province over a vaccine scandal in which improperly stored or expired vaccines were illegally sold in many areas of the country since 2011, according to a Xinhua report.

China /CIA
China /CIA

The investigation involves 12 vaccines, 2 immune globulin and one therapeutic product.

On Sunday officials released the names of 300 people who purchased vaccines from them across 24 provinces in China—two-thirds of the country.

The World Health Organization responded by essentially saying the concern is mostly in possible loss of efficacy:

WHO is aware of reports of vaccines being purchased by a private family and resold to hospitals and clinics. Chinese authorities are currently investigating the case and will make the results public in coming days. WHO awaits the investigation results and stands ready to provide support to national health authorities.

Vaccines need to be stored and managed properly or they can lose potency and become less effective. It is important to note, however, that improperly stored or expired vaccine seldom if ever causes a toxic reaction – therefore there is likely to be minimal safety risk in this particular situation. Rather, the risk to children from administering expired or improperly stored vaccine is lack of protection from the disease for which the vaccine was intended.

Vaccines used in China’s Expanded Program on Immunization are known to be safe and effective. The program vaccines have made China free from polio and have reduced vaccine preventable diseases such as hepatitis B among children to very low levels in China. WHO encourages parents continue to protect their children from vaccine preventable diseases through China’s routine Expanded Program on Immunization.