Effects of vaccination on invasive pneumococcal disease in South Africa.
BACKGROUND
In South Africa, a 7-valent pneumococcal conjugate vaccine (PCV7) was introduced in 2009 with a three-dose schedule for infants at 6, 14, and 36 weeks of age; a 13-valent vaccine (PCV13) replaced PCV7 in 2011. In 2012, it was estimated that 81% of 12-month-old children had received three doses of vaccine. We assessed the effect of vaccination on invasive pneumococcal disease.


METHODS
We conducted national, active, laboratory-based surveillance for invasive pneumococcal disease. We calculated the change in the incidence of the disease from a prevaccine (baseline) period (2005 through 2008) to postvaccine years 2011 and 2012, with a focus on high-risk age groups.


RESULTS
Surveillance identified 35,192 cases of invasive pneumococcal disease. The rates among children younger than 2 years of age declined from 54.8 to 17.0 cases per 100,000 person-years from the baseline period to 2012, including a decline from 32.1 to 3.4 cases per 100,000 person-years in disease caused by PCV7 serotypes (-89%; 95% confidence interval [CI], -92 to -86). Among children not infected with the human immunodeficiency virus (HIV), the estimated incidence of invasive pneumococcal disease caused by PCV7 serotypes decreased by 85% (95% CI, -89 to -79), whereas disease caused by nonvaccine serotypes increased by 33% (95% CI, 15 to 48). Among adults 25 to 44 years of age, the rate of PCV7-serotype disease declined by 57% (95% CI, -63 to -50), from 3.7 to 1.6 cases per 100,000 person-years.


CONCLUSIONS
Rates of invasive pneumococcal disease among children in South Africa fell substantially by 2012. Reductions in the rates of disease caused by PCV7 serotypes among both children and adults most likely reflect the direct and indirect effects of vaccination. (Funded by the National Institute for Communicable Diseases of the National Health Laboratory Service and others.).
From the Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases (NICD), National Health Laboratory Service (NHLS) (A.G., L.G., V.Q., S.M., C.M., S.A.M., C.C.), Medical Research Council, Respiratory and Meningeal Pathogens Research Unit (A.G., L.G., S.A.M.), and Department of Science and Technology/National Research Foundation, Vaccine-Preventable Diseases (S.A.M.), University of the Witwatersrand - all in Johannesburg; the Influenza Division (S.T.) and Division of Bacterial Diseases (E.R.Z., J.R.V., C.G.W.), Centers for Disease Control and Prevention, and Hubert Department of Global Health, Rollins School of Public Health, and Division of Infectious Diseases, School of Medicine, Emory University (K.P.K.) - all in Atlanta; and the Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore (K.L.O.).
Anne
A
von Gottberg
Linda
L
de Gouveia
Stefano
S
Tempia
Vanessa
V
Quan
Susan
S
Meiring
Claire
C
von Mollendorf
Shabir A
SA
Madhi
Elizabeth R
ER
Zell
Jennifer R
JR
Verani
Katherine L
KL
O'Brien
Cynthia G
CG
Whitney
Keith P
KP
Klugman
Cheryl
C
Cohen
D000328:Adult; D015658:HIV Infections / Q000150:complications; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D015994:Incidence; D007223:Infant; D010403:Penicillin Resistance; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000008:administration & dosage; D011159:Population Surveillance; D065288:Serogroup; D013019:South Africa / Q000453:epidemiology; D013296:Streptococcus pneumoniae / Q000145:classification; D018074:Vaccines, Conjugate
D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate