Merck Sharp & Dohme Asia (MSD) said they regretted a recent mistake printed on their vaccines’ instructions, yet confirmed it posed very low risk to human health at a press briefing Monday.

Early this month, a batch of the vaccine MMRII imported to Vietnam on February 11 was labeled with instructions saying “for intramuscular injection” rather than “for subcutaneous injection” as normally prescribed.

Dr. Bui Thi Thanh Thuy from MSD cited a World Health Organization’s epidemiological report in April, 2004 as saying the measles vaccine is generally injected subcutaneously but also effective when administered intramuscularly.

She also quoted the recommendations of the Advisory Committee on Immunization Practices, an agency under the US Center for Disease Control and Prevention.

In Europe, the vaccine is licensed to be used for both routes, Thuy said at the briefing in Ho Chi Minh City with the participation of local experts, including Professor Do Gia Canh from the National Institute of Hygiene and Epidemiology.

“The risks posed to people receiving intramuscular injections of the vaccine are very low,” she said.

Canh confirmed that both applications have the same immunogenicity and side-effects.

Professor Pham Hoang Phiet from the HCMC University of Medicine and Pharmacy agreed with Canh, saying only patients with blood diseases risked complications when inoculated intramuscularly.

On March 9, MSD reported immediately to the Drug Administration of Vietnam about the error after receiving a call from a preventive health center asking why the vaccine’s label said to inject it into muscle while it is generally for subcutaneous use, Thuy said.

About two thirds of the 40,000 vials of vaccine batch Lot K6572, however, had already been consumed, MSD Chief Representative in Vietnam Kha My Linh, said.

“But we haven’t received any reports about the intramuscular use for the vaccine from our customers,” Thuy said.

Doctors have probably continued injecting the vaccine under the skin despite the labeling error, because they are in the habit of injecting the vaccine underneath skin, according to Dr. Huynh Thi Duy Huong from the same university.

MSD representatives said this is the first time they had imported the vaccine with all labels in Vietnamese as regulated by the Ministry of Health, adding that only the label on the vial had the wrong information while the outer carton and insert were correct.

Previously, only the insert was printed in Vietnamese, while the other packaging was in English, according to Thuy.

Linh said MSD would follow ministry guidelines and at this point they had not been asked to withdraw the batch from pharmacy shelves, but only to inform related agencies of the error.

Since there was no difference in the two routes, the company should apply for use of intramuscular injection, to avoid confusing the public, Huong urged.

“We will immediately apply for vaccination by intramuscular and subcutaneous injection,” Linh said.

Merck Sharp & Dohme Asia Ltd. is a branch of Merck Sharp & Dohme in New Jersey, US.

Reported by Thanh Nguyen