Merck, GlaxoSmithKline face hepatitis A vaccine shortage amid U.S. outbreaks

It was only August when Merck and GlaxoSmithKline had to deal with a global shortage of their hepatitis B vaccines, and now unexpected demand in the U.S. has sent both companies scrambling to cope with a shortage of hepatitis A shots.

Since March, the CDC’s Division of Viral Hepatitis has identified hepatitis A outbreaks in several cities in California, Michigan and Utah, especially among people who are homeless and people who use drugs. Besides thoroughly washing hands, the CDC recommends vaccination as the best way to prevent hepatitis A, and vaccines are also used as postexposure prophylaxis.

Over the past six months, those ongoing outbreaks have resulted in supply stress for vaccine makers Merck and GSK, which sell U.S.-licensed hepatitis A shots Vaqta and Havrix, respectively.

“Merck is working through some manufacturing constraints this year related to our growing global demand and unexpected demand in markets due to lack of competitive supply,” the company said in a statement to FiercePharma.

After putting Vaqta on backorder since the shortage was identified, Merck said it just began shipping the shot in single-dose vials at the end of October. Prefilled syringes won’t be available until the first quarter of next year. The company further pledged to continue to increase its manufacturing capacity to meet global demand in 2018.

RELATED: Merck and GlaxoSmithKline production issues lead to global shortage of hepatitis B vaccine

In a separate statement shared with FiercePharma, GSK also said that recent outbreaks in the U.S. have created unexpected demand for adult hepatitis A vaccines, and that it still has prefilled syringes and a limited supply of vials in stock.

“We are working diligently to increase our supply, as well as working with CDC to monitor and manage public and private vaccine orders to help ensure that our vaccine is directed to areas of greatest need,” GSK said in the statement.

The hepatitis A vaccine shortage emerged hard on the heels of a hepatitis B vaccine supply issue that also involves Merck and GSK.

Merck previously told FiercePharma that supply interruptions for the adult formulation of its hepatitis B shot Engerix-B began in the first quarter of 2017. The company doesn’t expect to be distributing the adult shot at least until the end of 2018, and its pediatric version is expected to be unavailable until early 2018.

GSK currently has sufficient supplies of its hepatitis B shot to fill the gap left by Merck, but the British pharma also previously told FiercePharma that it’s dealing with reduced manufacturing capacity for hepatitis A and B antigens. Dynavax recently won FDA approval for its competitor, Heplisav-B, and plans to launch early next year.

As of early November, the CDC has recorded 644 hepatitis A cases, 420 hospitalizations and 21 deaths in California this year. In Michigan, there have been 495 cases, 416 hospitalizations and 19 deaths.

Editor's note: This story has been edited with the correct name for GlaxoSmithKline's hepatitis B vaccine.