In December of 2011, the FDA approved the expanded use of PCV13 under an “Accelerated Approval” process to include adults 50 years of age and older. The “Accelerated Approval” process allows products targeted to treat a serious condition or fill an unmet need the opportunity to receive quicker FDA approval based on laboratory tests or other measurements believed to possibly predict a clinical benefit.
In this case, a comparison was made between antibody responses of individuals receiving either PCV13 or Merck’s 23-valent pneumococcal polysaccharide vaccine (PPSV23). PCV 13 was found to have a similar or higher antibody response when compared to PPSV23 and the FDA permitted this laboratory finding to fulfill the requirement needed to receive “Accelerated Approval”, despite knowing that the level of vaccine-induced antibodies required to protect an individual against a particular strain of pneumococcal infection was unknown.
While the ACIP declined to routinely recommend PCV13 for adults over the age of 50 following the FDA’s approval to expand its usage, the committee did vote to recommend the vaccine for use in immunocompromised adults 19 years of age and older, in June of 2012. The FDA, however, did not approve PCV13 for use in adults 19 to 49 until July 11, 2016.
In 2014, the CDC updated its recommendations for the use of PCV13 and recommended that the vaccine be administered to all seniors 65 and older in addition to the previously recommended PPSV23 vaccine; however, by October 2018, it was reported during an ACIP meeting that this recommendation had not reduced pneumonia rates among persons 65 years and older.
In June 2019, ACIP voted to pull back from its 2014 recommendation and stated that healthy seniors 65 and older could consider this vaccination after discussions with their physician. PCV13 was still recommended for seniors 65 years and older who had chronic health conditions and a single dose of PPSV23 was still recommended for all persons 65 and older.
Pneumococcal strains not covered within the vaccine have continued to emerge since the introduction of PCV13. Researchers in the United States have noted that while invasive pneumococcal disease has decreased since the introduction of pneumococcal conjugate vaccines, S. pneumoniae strains have adapted and antibiotic resistant non-vaccine strains have emerged. These non-vaccine type strains include strains 33F, 22F, 12, 15B, 15C, and 23 A.
Korea, Taiwan, and several Western European countries, have also reported an increase in pneumococcal strains not covered by PCV13 and scientists continue to recommend pneumococcal strain monitoring and further development of vaccines in response to continued emergence of non-vaccine type strains.
