Recently reviewing my on-line medical information from Winding Waters Clinic, I noticed I had received 2 doses of pneumococcal vaccine: one dose of PPSV23 in 2013 and a second dose of a similar vaccine (PCV13) in 2014. Despite a nearly 40 year career of wallowing in antibiotic related teaching and research, I knew very little about the vaccine, thus hatching today’s Mountain Medicine column.
In general, there are 3 good reasons for vaccination, and only one is obvious. First, there are direct effects; you may avoid the infection that the vaccine is designed to prevent. Second, without an infection, you will avoid a course of antibiotics, not a trivial concern in this age of increasing resistance (Mountain Medicine, May 30, 2018). Finally, for communicable infections there are indirect effects; you will not pass on to others the infection you did not acquire.
What infection does pneumococcal vaccine prevent? Pneumococcal vaccine is designed to prevent most serious infections caused by the bacterium Streptococcus pneumoniae (also called pneumococcus). Pneumococcus is frequently present in the human respiratory tract but usually does not cause infection. It is spread from person to person by droplets from coughing and sneezing, and some will develop an infection.
Pneumococcus can cause 3 serious infections. It is the most common cause of bacterial pneumonia and meningitis, and it can get into the blood and cause a severe syndrome called sepsis. Pneumococcus can infect any age group, but the most vulnerable include infants and children, adults over 65 years, and those with a compromised immune system. Pneumococcus is increasingly resistant to penicillin and erythromycin-like drugs, so prevention of infection becomes critical.
What is pneumococcal vaccine? There are 2 pneumococcal vaccines; both have forgettable names from abbreviation of their chemical composition. PCV13 (Prevnar 13) was FDA approved in 2010, and PPSV23 (Pneumovax 23) was approved in 1983. Although Streptococcus pneumonia is a specific bacterium, there are over 90 variations (called serotypes).The numbers 13 and 23 refer to the number of serotypes included in each vaccine. These serotypes are the most common causes of human diseases; both vaccines are useful in specific circumstances. The vaccines are highly effective in children (only PCV13 is effective in children less than 2 years), they prevent serious pneumococcal infection (sepsis and meningitis) in 60 to 80% of adults over 65 years, but are less effective in immunocompromised patients.
Who should receive the vaccine, and when? Infants should receive PCV13 at 2, 4 and 6 months, with a final dose at 12-15 months. Healthy adults should receive PCV13 at age 65, followed by PPSV 23 one year later. Immunocompromised children (over 2 years) and adults with chronic diseases and high risk for infection should receive PCV13 and PPSV23.
In actual practice these guidelines can become complex and you will need to consult your healthcare provider. The Centers for Disease Control and Prevention (CDC) provide additional on-line expert advice: www.cdc.gov/vaccines/vpd/pneumo/hcp/index.html, and CDC created an app to assess an individual’s vaccination schedule: www.cdc.gov/vaccines/vpd/pneumo/hcp/pneumoapp.html. Based on my immunization history, the app informs me that I am “complete”.
The CDC reported that approximately 80% of Oregon children received at least 4 doses of PCV13 in 2016. US vaccination rates in 2017 for healthy adults over 65 years was nearly 70%. In contrast, US vaccination rates for adults under 65 years with high risk for pneumococcal disease was only 25%.
Who should not receive the vaccine, and what are the adverse effects? A previous serious reaction to pneumococcal vaccine will preclude readministration. Temporary pain at the injection site, mild fever and muscle aches are possible.
What’s new? Immunization guidelines for 2020 will be published soon. It’s likely existing recommendations for PCV13 in healthy adults over 65 (above) will become optional or cease altogether. This is because PCV13 administered to children has been so successful that the indirect effect has been a dramatic reduction in serious adult infections. Finally, new vaccines (PCV15 and PCV20) are in the last phases of clinical investigation.
The take home? Prevention of infection is far preferable than is treatment, and treatment options are declining.
Ron Polk lives in Lostine and edits Mountain Medicine in collaboration with Wallowa County medical practitioners.