People age 65 and older should get two separate vaccines to protect against pneumonia and other infections starting this fall, a change of decades-old advice, according to new health guidelines.
An advisory panel to the U.S. Centers for Disease Control and Prevention recently recommended that people get a second vaccine, called Prevnar 13, because of limitations with the older shot, called Pneumovax 23.
Both vaccines, which are usually administered once in older adults, are designed to protect against infections of the bacterium Streptococcus pneumoniae, but they work in different ways. Prevnar 13 has been used by itself to vaccinate children since 2010 and has proven effective.
Every year, an estimated just under one million people in the United States get pneumococcal pneumonia—a lung infection, whose symptoms include fever, cough and chest pain—and 5% to 7% of patients die from it, according to the CDC. It is typically treated with antibiotics, but some strains have developed resistance to those drugs.
Pneumococcal bacteria also can cause so-called invasive diseases, including bacteremia, a bloodstream infection, and meningitis, which affects the brain and spinal cord. The CDC estimated there were over 3,000 deaths in the U.S. from these two diseases in 2012.
Pneumococcal infections are more likely to cause illness in older people, children younger than 2 years old and those with conditions that weaken the immune system, such as diabetes, according to the CDC. The bacteria are transmitted by contact with saliva or mucus. Children are carriers, harboring the bug in their noses or throats, and the bacteria are a common cause of middle-ear infections in kids.
The CDC is expected to formally adopt the advisory panel’s recommendations in coming weeks.
The addition of Prevnar 13 to the guidelines continues a campaign by vaccine manufacturers and public-health authorities to expand routine vaccinations to adults from children. In recent years the CDC has urged more adults to receive seasonal influenza vaccines, and recommended adults 60 and older get a shot to reduce their risk of shingles.
In an unusual move, the CDC panel said it would revisit its decision in 2018 and might remove its Prevnar 13 recommendation if the number of people getting sick declines sufficiently. The routine use of Prevnar 13 in children since 2010 has had what scientists call a herd effect, which occurs when vaccination of one part of the population also reduces the transmission of a disease to unvaccinated people. If the herd effect continues to rise, it could lessen the need for Prevnar 13 in adults.
Some members of the CDC panel said the relatively high cost of Prevnar 13 also factored into their recommendation to revisit the guidelines. Prevnar 13 costs about $135 a dose versus $68 for Pneumovax 23. The federal Medicare program, which currently pays for one pneumococcal vaccine per older adult in most cases, might not begin covering a second shot until 2016.
Because of Prevnar 13’s price, “we want to use it as long as we need to use it to provide protection, but we probably don’t want to use it beyond that time period,” said Ruth Karron, a member of the CDC advisory panel an immunization researcher at Johns Hopkins Bloomberg School of Public Health.
Prevnar 13 replaced an older shot—Prevnar 7—that came out in 2000 and was also recommended mainly for children. Its manufacturer, Pfizer Inc., later gathered enough evidence to support its use in adults.
People 65 and older who haven’t received any pneumococcal vaccine are now recommended to receive Prevnar 13 first, followed by Pneumovax 23 at least six to 12 months later. Those already vaccinated with Pneumovax 23 should get Prevnar 13 at least one year later, the panel voted.
Clinical results show that even receiving the two vaccinations can’t guarantee protection against pneumococcal disease in everyone, nor do they protect against infections caused by viruses and fungi.
More than half of older adults have received at least one shot of Pneumovax 23, according to the CDC. The vaccine, introduced in 1983, is designed to protect against 23 serotypes, or strains, of Streptococcus pneumoniae. It is known as a polysaccharide vaccine because it incorporates sugar coatings of the bacteria, which trigger the body’s immune system to make antibodies to fight the bacteria.
Those who receive Pneumovax 23 at or after age 65 should only get a single dose, while people who have gotten it before age 65—if they had a chronic disease, for instance—should get another dose if at least five years have passed. The CDC says the vaccine is effective against invasive disease, including bacteremia and meningitis, but less effective in preventing pneumococcal pneumonia.
John Grabenstein, an executive director of health and medical affairs in Merck’s vaccines unit, said there is some evidence Pneumovax 23 can help ward off pneumonia. He said a 2010 study published in the British Medical Journal found the vaccine reduced the incidence of pneumonia among residents in Japanese nursing homes compared with a placebo.
Prevnar 13 is designed to protect against 13 strains of the bacteria, including 12 types also targeted by Pneumovax 23. But Prevnar 13 is designed differently than Pneumovax 23. It contains polysaccharides that are fused to proteins, forming a so-called conjugate, which is believed to help trigger a stronger immune response against certain bacteria strains.
In 2011, the Food and Drug Administration approved the use of Prevnar 13 in adults age 50 and older. But the CDC’s advisory panel delayed its recommendation until it received results of a large clinical study testing whether a vaccine-induced immune response actually translated into reduced risk for disease.
The study, presented at a medical conference in March, found that Prevnar 13 reduced by about 45% the risk of a first case of pneumonia caused by the targeted 13 bacterial strains compared with a placebo. The vaccine also reduced by 75% the risk of a first case of an invasive disease caused by the targeted strains. The study involved about 85,000 people in the Netherlands, where Pneumovax 23 isn’t routinely administered to older adults. Pfizer, which conducted the study, wanted to demonstrate Prevnar 13’s effectiveness in an unvaccinated population.
The addition of Prevnar 13 in older adults will change the landscape if it goes into full recommendation. CDC’s vaccine advisory panel is now recommending that both be given.