Reducing Pneumonia Morbidity and Mortality with Pneumococcal Vaccines

July 24, 2012: Content on this page kept for historical reasons.

Division of Bacterial Diseases (DBD) News Bulletin

Summer 2012

Through partnerships and collaborations, staff from the Respiratory Diseases Branch (RDB) work to reduce death and disability from vaccine-preventable respiratory diseases both domestically and globally. One major global initiative underway is to reduce disease and deaths from pneumonia among children younger than 5 years of age in developing countries.

World-wide, nearly 1.6 million children die of pneumonia each year; with half of these deaths occurring in Afghanistan, Pakistan, India, Nigeria, and the DR Congo. Implementation of pneumococcal conjugate and Haemophilus influenzae type b (Hib) vaccines will prevent the two most common causes of pneumonia deaths. Almost all of 800,000 child deaths due to Streptococcus pneumoniae each year occur in low and middle-income countries.

In recent years, the pneumococcal conjugate vaccine (PCV), a highly effective preventive intervention that has dramatically reduced the burden of pneumococcal disease in high-income countries, has been introduced to areas of the world with the greatest pneumococcal disease burden—the low and middle income countries. Pneumococcal vaccines have reached 17 GAVI-supported countries in recent years and within the last few months, successful pneumonia vaccine campaigns have been launched in Nigeria and Ghana.

Pictured above are Cynthia Whitney and Matthew Moore with a poster highlighting data on the early effects of PCV13 on disease in the US. RDB staff presented 28 oral and poster presentations at the 8th International Symposium on Pneumococci and Pneumococcal Diseases (ISPPD) in Iguacu Falls, Brazil in March. The bi-annual symposium brings together professionals in pneumococci and pneumococcal diseases to raise global awareness and improve standards of diagnosis, prevention and treatment. Jennifer Verani, Lesley McGee, Laura Conklin and Gloria Carvalho also participated in the symposium.

Of special note, with regard to PCV, are invitations for DBD experts to speak at prestigious international conferences, including the 2012 presentations by Matt Moore and Chad Cox at ISPPD and ICEID, underscoring an increased interest in 13-valent pneumococcal conjugate vaccine (PCV13). Moore and Cox presented data on the early effects of PCV13 using United States data from CDC’s Active Bacterial Core surveillance before and after the introduction of PCV13 in March 2010 that highlighted the potential direct and indirect effects of the vaccine. Their finding of a decrease in overall invasive pneumococcal disease (IPD) rates among vaccine-eligible children younger than 2 years of age was discussed along with their findings showing a decrease in IPD among all age groups (except children aged 5-17 years) during the 4th quarter of 2011—an early indicator of potential indirect effects of the vaccine. Moore and Cox found no evidence of an increase in IPD rates due to non-vaccine serotypes (i.e. replacement disease). They confirmed that continued surveillance is needed to evaluate future trends, but early signs indicate both a direct and indirect effect of the vaccine in reducing IPD.

RDB activities to address pneumonia are many and varied. In recent months, RDB has collaborated with GAVI to evaluate pneumococcal vaccine impact in South Africa and completed studies on the impact of Hib vaccine. A clean burning cookstoves project in rural western Kenya continues to gather data that will help local health officials and global partners assess use of these stoves as a strategy to reduce indoor air pollution and help prevent pneumonia. To help build in-country capacity for laboratory activities, laboratory field staff from all 6 IEIP and 4 NIC sites have received training at CDC and many will also receive on-site trainings, as necessary. Laboratory trainings and assessments for WHO regional labs may also be offered. A manual to guide assessment of Hib vaccine and PCV impact in developing countries developed by RDB in partnership with WHO is being successfully used.

At present, little is known about how well PCV is going to perform in the areas of the world where the vaccine is needed most because the epidemiology of pneumococcal disease in low and middle-income countries is different from that of wealthier countries and the currently available PCV formulations were licensed based on immunogenicity data (rather than trials with clinical outcomes). In addition, because of the high cost of PCV, many countries are introducing the vaccine with a reduced dose schedule, and the effectiveness of such schedules is unknown.

According to Moore, "Preliminary data from studies in South Africa, Brazil, and Uruguay provide reassuring evidence that in most children, the vaccines are highly protective against disease caused by the serotypes included in the vaccines." However, Moore cautions, saying "Data from South Africa showing a lower than expected effectiveness among HIV-infected children have already led to a policy change in that country – an additional dose in the routine schedule for HIV-infected children. We will have to do more research to better understand PCV impact and its effectiveness – especially in low-income countries."

Already, countries in Latin America, Africa and Asia have introduced PCV into their routine immunization schedules and within the next few years, a number of other countries are expected to change their immunization policies to include PCV. RDB’s ongoing work with partners and ministries of health in geographically diverse countries such as Malawi, Kenya and Mozambique will provide important evidence for the introduction and sustained use of PCV globally.