Vaccines against varicella-zoster virus and Streptococcus pneumonia can be safely delivered at the same time, contrary to a U.S. Food and Drug Administration recommendation, researchers said.
Giving the two vaccines together was no more likely to lead to herpes zoster -- a painful, viral skin rash also known as shingles -- than giving them between 30 days and a year apart, according to a study by Hung Fu Tseng and colleagues at Southern California Kaiser Permanente in Pasadena.
The finding casts doubt on a 2009 FDA recommendation that the zoster vaccine, Zostavax, should not be administered concurrently with Pneumovax 23, the 23-valent pneumococcal polysaccharide vaccine, Tseng and colleagues suggested online in the journal Vaccine.
They also noted that the U.S. Centers for Disease Control and Prevention continues to recommend that both vaccines be given together if a patient is eligible for them.
The study results "provide no indication that this recommendation could compromise the immune response that is necessary to protect" against herpes zoster, the researchers concluded.
The issue is important, they noted, because the FDA recommendation presents a barrier to vaccine coverage and increases administration costs, since patients must show up at -- and pay for -- two appointments with their doctors.
To clarify the issue, they turned to the electronic health records of Southern California Kaiser Permanente, which contain data on approximately 3.4 million people.
They looked for patients, 60 or older, who got both vaccines on the same day between Jan. 1, 2007 and June 30, 2010.
As a control group, they included patients given the zoster vaccine during the same period, but who got the pneumococcal vaccine from a year to 30 days earlier.
All told, the same-day group included 7,187 patients and there were 7,179 controls.
Over the study period, the researchers found, there were 114 incident cases of herpes zoster, 56 in the same-day cohort and 58 among the controls.
The researchers cautioned, that larger studies may have to be done in order to confirm the findings. However, Dr. Michael Oxman of the VA San Diego Healthcare System and colleagues called the findings are "particularly important and noteworthy."
In an accompanying editorial, they argued that the recommendation not to give the two vaccines at the same time "increased the already challenging task of delivering the recommended vaccines to older adults."
FDA regulators erred when they assumed that antibodies to the virus, besides indicating the immunogenicity of the vaccine, also correlated with protection, Oxman and colleagues argued.
"This was almost certainly an inappropriate assumption, as demonstrated by the results of the study," they wrote.