Pharmaceutical companies are closely monitoring the supply of hepatitis A vaccines in the wake of a sudden spike in the hepatitis A infections in Seoul and its vicinity. Hepatitis A is a viral liver disease, and the virus is transmitted through contaminated food or direct contact with an infected person.

(From top) GSK's hepatitis A vaccine Havrix, Sanofi Pasteur's Avaxim, and MSD's Vaqta

In Korea, GSK, Sanofi Pasteur and MSD sell hepatitis A virus antigen Havrix, Avaxim, and Vaqta, respectively. The three companies are concerned that their vaccine supply will be similar to the level of last year.

“We have about 200,000 doses of Havrix, which is twice the normal annual sales,” a GSK official said. “Although we don’t expect that the number of patients will not increase significantly to consume all the vaccines in stock, we are still paying attention to the number of the infected people.”

Sanofi Pasteur said the local hepatitis A vaccine market needs about 200,000-300,000 doses a year. “This year, we have secured 200,000 doses of Avaxim which is about 150 percent of the last year’s sales,” it said.

MSD Korea said it has around 110-120 percent of the last year’s sales of Vaqta products. “If there is a request from the government for extra supply, we need discussions,” it said.

Usually, pharmaceutical firms prepare 110-120 percent of the previous year’s quantity of vaccines that are not included in the national immunization program (NIP) because they have to discard all of the leftover vaccines.

According to the Korea Centers for Disease Control and Prevention (KCDC), the reported cases of hepatitis A infections spiked to 3,597 during the January-April 28 period, up 237 percent from the same period of 2018. About 73 percent of the cases (2,611 people) were those in their 30s or 40s. Including those in their 20s, 90.1 percent of the infected people (3,096) were in their 20s-40s.

Under the NIP, the government supports free hepatitis A vaccination for children who are born in 2012 or after. Since 2015, the authorities have also offered free hepatitis A vaccines for Korean men enlisting in the military.

Children born before 2012, adults who began the military service after 2015, and those aged 50 or more who have been naturally exposed to hepatitis A virus due to poor hygiene are not likely to be infected with the virus. Thus, the recent hepatitis A infections have occurred among people aged between seven and 49, according to the health authorities.

To prevent hepatitis A infection, the health authorities advised that young children aged 12-23 months, chronic liver disease patients without immunity against hepatitis A, workers at restaurants, physicians, those who had contact with hepatitis A patients within the recent two weeks, high-risk pediatric patients, or adults get hepatitis A vaccination.

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