Incidence of pneumonia is not reduced by pneumococcal conjugate vaccine

Publication: Bulletin of the World Health Organization; Type: Letters
Article DOI: 10.2471/BLT.08.054692

Incidence of pneumonia is not reduced by
pneumococcal conjugate vaccine
Sona Chowdharya & Jacob Puliyela
a Department of Pediatrics, St Stephens Hospital, Tis Hazari, Delhi 110054, India.
Correspondence to Jacob Puliyel (e-mail: puliyel@gmail.com).
(Published online: 1 September 2008)

Madhi et al..1 write that the pneumococcal conjugate vaccine (PCV) is an effective
instrument for pneumonia prevention in children. This is not strictly true. WHO data2
suggest that there are 450 million cases of pneumonia each year and that it causes 3.9
million deaths. In the sub-Saharan region of Africa, 1 022 000 die and 702 000 die in
south Asia.1 The pneumonia referred to is “clinical pneumonia” – a diagnostic syndrome
within the Integrated Management of Childhood Illness – WHO and United Nations
Children’s Fund (UNICEF) system for triage and clinical management in developing
countries.3 The Cochrane database4 states that PCV does not reduce the incidence of
clinical pneumonia, although it has been shown to reduce vaccine-serotype bacteraemic
pneumonia and radiological pneumonia. The benefit of reducing bacteraemic pneumonia
and radiological pneumonia is so minimal that it has no effect on “clinical pneumonia”.
Poor nations will need to assess its cost utility carefully.

A study from the Gambia showed that mortality was 16% lower in a PCV
immunized group compared to placebo recipients (25.2/1000 children years versus
30.1/1000 children years).5 Data are also provided on adverse effects and deaths within 1week of receiving any dose of the vaccine or placebo. The mortality benefit was seen inthe first week after injection, well before vaccine efficacy could have been established.
There were 12 deaths in the vaccine group and 15 among controls (23.8/1000 children
years versus 29.8/1000 children years). This suggests that factors other than vaccine
efficacy are responsible for the difference in mortality between the groups compared.
There is also another issue that we hope to raise here. The paper states that the
vaccine programme would exceed the WHO threshold in 69 eligible countries. The
authors assert that these findings are conservative in the sense that they did not assume
any herd protection and did not assume protection beyond the age of 2.5 years
has cautioned against this trend of noting the “positive” uncertainties (herd immunity,
protection beyond 2.5 years) without reporting the “negative” ones (serotype
replacement,7 increased incidence of asthma),8 which could dampen enthusiasm for the
intervention.

References
1. Madhi SA, Levine OS, Hajjeh R, Mansoor OD, Cherian T. Vaccines to
prevent pneumonia and improve child survival. Bull World Health Organ
2008;86:365-372. PMID:18545739 doi:10.2471/BLT.07.044503
2. Revised global burden of disease 2002 estimates. Geneva: WHO.
Available from:
http://www.who.int/healthinfo/bodgbd2002revised/en/index.html [accessed
5 August 2008].
3. Integrated Management of Childhood Illness. Geneva: WHO; 2000.

4. Lucero MG, Dulalia VE, Parreno RN, Lim-Quianzon DM, Nohynek H,
Makela H, et al. Pneumococcal conjugate vaccines for preventing vaccinetype
invasive pneumococcal disease and pneumonia with consolidation on
x-ray in children under two years of age. Cochrane Database Syst Rev
2004;CD004977. PMID:15495133
5. Cutts FT, Zaman SM, Enwere G, Jaffar S, Levine OS, Okoko JB, et al.;
Gambian Pneumococcal Vaccine Trial Group. Efficacy of nine-valent
pneumococcal conjugate vaccine against pneumonia and invasive
pneumococcal disease in The Gambia: randomised, double-blind,
placebo-controlled trial. Lancet 2005;365:1139-46. PMID:15794968
doi:10.1016/S0140-6736(05)71876-6
6. Beutels P. Potential conflicts of interest in vaccine economics research: a
commentary with a case study of pneumococcal conjugate vaccination.
Vaccine 2004;22:3312-22. PMID:15308354
doi:10.1016/j.vaccine.2004.03.001
7. Eskola J, Kilpi T, Palmu A, Jokinen J, Haapakoski J, Herva E, et al.;
Finnish Otitis Media Study Group. Efficacy of a pneumococcal conjugate
vaccine against acute otitis media. N Engl J Med 2001;344:403-9.
PMID:11172176 doi:10.1056/NEJM200102083440602
8. Klugman KP, Madhi SA, Huebner RE, Kohberger R, Mbelle N, Pierce N;
Vaccine Trialists Group. A trial of a 9-valent pneumococcal conjugate
vaccine in children with and those without HIV infection. N Engl J Med
2003;349:1341-8. PMID:14523142 doi:10

"It is now 30 years since I have been confining myself to the treatment ofchronic diseases. During those 30 years I have run against so many histories of littlechildren who had never seen a sick day until they were vaccinated and who, in the severalyears that have followed, have never seen a well day since. I couldn't put my finger onthe disease they have.. They just weren't strong. Their resistance was gone. They wereperfectly well before they were vaccinated. They have never been well since. "---Dr. William Howard Hay