Pneumococcal Conjugate (PCV) Vaccine

The pneumococcal conjugate vaccine (PCV) is a vaccine to protect against disease caused by the bacterium Streptococcus pneumoniae, commonly known as pneumococcus. It is a bacterial infection common in young children and some older children and adults. The vaccine is given to infants with a booster for toddlers.

The disease

Pneumococcus causes a variety of mild and serious diseases.  It is the most common cause of ear infections (otitis media), sinus infections, and pneumonia in children, and is a common cause of pneumonia in adults.  It can also cause meningitis and blood infections (bacteremia or sepsis).  Many people carry the germ normally in their noses and throats, and it causes disease when a cold or flu cause the person’s normal defenses to break down.  It is contagious in the sense that people can spread it to other people, but not in the sense that everyone who catches the germ becomes ill.  It does spread from person to person and from child to child, but this is usually as one carrier to another.  For example, ear infections and sinus infections are not contagious.

After the success of the HIB vaccine at wiping out HIB disease, pneumococcus became the most common cause of childhood meningitis and other serious infections in young children, though it did not become more frequent itself.  Because of the serious diseases it causes, and also because it is a common cause of ear infections and pneumonia, a more effective vaccine was sought.  A polysaccharide vaccine has been available since 1977, but this kind of vaccine does not work in children less than 2 years of age.  Conjugate vaccines, like the HIB vaccine, are much more effective in young children, and a pneumococcal conjugate vaccine was developed against the 7 most common strains in 2000.  These 7 strains cause 80% of infections in children less than 6 years of age. In 2010, the 7-strain vaccine was replaced with a 13-strain vaccine in order to cover more strains, some of which had become more common after the 7-strain vaccine began.

The vaccine

The current vaccine is the 13-strain pneumococcal conjugate vaccine (PCV-13) made by Wyeth/Pfizer. This is the only brand of vaccine available. It replaced the 7-strain vaccine in 2010. The 7-strain vaccine had been in use since 2000.  It is given at ages 2, 4, and 6 months of age with a booster dose at 12-15 months of age.  Unvaccinated children ages 24-59 months only need one dose; unvaccinated children ages 12-23 months only need 2 doses.  Unvaccinated children 7-11 months old need 2 doses followed by a booster dose.  It is given intramuscularly and does not contain thimerosal as a preservative.

Side effects

The most common side effects are local reactions at the injection site, including pain, redness, or swelling, occurring in 10-20% of children.  This usually lasts less than 48 hours, though the leg may be sore for several days.  These reactions are more common with the later doses than they are with the first.  Fever is not a common side effect.  There are not any known severe side effects or risks of the vaccine.

Risks vs. benefits

The vaccine has been shown to be very effective at reducing serious disease due to pneumococcus, including meningitis and blood infections.  It has also reduced the number of ear infections and cases of pneumonia.  It has also reduced the overall incidence of pneumococcal disease even in unvaccinated children due to less transmission of the germ.  The vaccine has no known short or long-term risks or serious side effects, so it seems that the benefits outweigh the risks.

Resources

PCV13 (Pneumococcal Conjugate) Vaccine Information Statement (CDC)

References

Originally published June 13, 2005. Last updated January 26, 2016.