On May 28, 2015, Himal Lal and coworkers, in collaboration with GSK Vaccines, published the results of a large clinical trial of a herpes zoster vaccine (Lal H, Cunningham AL, Godeaux A, et. al. Efficacy of an Adjuvanted Herpes Zoster Subunit Vaccine in Older Adults. N Engl J Med. 2015 May 28;372(22):2087-96).
The current shingles vaccine (Zostavax®) is made using the Oka strain of varicella vaccine. The difference between Zostavax, which is recommended for adults older than 60, and the varicella vaccine (Varivax®), which is recommended for all young children, is that Zostavax contains roughly 14 times more Oka strain of varicella vaccine than Varivax. Otherwise, the vaccines are identical.
The new shingles vaccine (HZ/su) is different. The new vaccine is made using only one protein from varicella-zoster virus (glycoprotein E, 50 micrograms). The other difference is that the HZ/su vaccine contains two adjuvants: 1) 50 micrograms of monophosphoryl lipid A (the same adjuvant used in one of the HPV vaccines, Cervarix®), and 2) 50 micrograms of QS21 (saponin, an adjuvant that is used in other countries but is not currently licensed for use in vaccines in the United States).
Researchers tested HZ/su in a placebo-controlled, prospective trial in 15,411 adults aged 50-59, 60-69, and older than 70. Patients were followed for an average of 3.2 years. Overall vaccine efficacy against shingles was a remarkable — 97.2 percent, with a range of 96.6 percent to 97.9 percent across the three age groups. These results are better than those found for Zostavax, where efficacy against shingles was about 67 percent.
The HZ/su vaccine clearly reduces the risk of shingles in people more than 50 years of age. Now the vaccine awaits longer term testing and approval of this novel adjuvant for use in the United States.