The US Food and Drug Administration on Oct. 20 approved Shingrix, the long awaited recombinant, adjuvant new shingles vaccine manufactured by UK drugmaker Glaxo SmithKline (GSK). Days earlier, Canada gave the green light. GSK is also seeking approval in  Europe, Australia and Japan.

The new vaccine can help prevent shingles in at least 90% of the population as well as reducing the risk of developing shingles by 51% and lowering the risk of postherpetic neuralgia by 67%, the Atlanta, Georgia-based Centers for Disease Control (CDC) has estimated. This compares with only 50-60% for the only other vaccine available in the US and Canadian markets, Merck & Co.’s Zostavax, from which it is thought likely to take market share. An added bonus is that the new drug is reportedly effective longer.

The CDC’s Advisory Committee on Immunization Practices is due to vote on the use of Shingrix at its meeting this week. If approved there, GSK said it will prepare to make the vaccine available to the public. All of Canada’s and most US healthcare providers or insurers are expected to cover the cost, especially for the target age group over 50 years of age or those with weakened immune systems.

The painful rash associated with shingles is caused by the varicella-zoster virus, which remains dormant in the system of people who have had chickenpox. While, for some, the virus remains inactive, stress and medication can cause a flare-up in others. The resulting nerve pain can last for several months or even years. An estimated 1 million Americans contract the disease annually.

Decisions by authorities in the two North American countries were based on phase 3 trials with the medication. The two-pronged trial in Canada is said to have shown that the GSK vaccine, given in two doses two to six months apart, is 97.2% effective in the target population and maintains a 90% efficacy in those 70 years old and older for at least four years.

Shingrix is one of three key launches that GSKs new CEO Emma Walmsley has said are a near-term focus. Considering the vaccine’s efficacy and safety profile, in addition to shingles' incidence and the severe pain associated with the infection, life science commercial intelligence firm Evaluate has predicted that the vaccine will achieve blockbuster status by 2022. Merck reported sales of $685 million for Zostavax in 2016.