Haemophilus influenzae type b is a leading cause of pneumonia and meningitis, an inflammation of the lining covering the brain and spinal cord. Each year, Hib kills approximately 400,000 children under five years of age, most of them in the developing world. It is also responsible for approximately three million cases of serious illnesses resulting in long-term consequences such as deafness, paralysis, mental retardation and learning disabilities.
Upon monitoring occurrence of bacterial meningitis due to Hib between 2001 to 2006, the study's authors saw marked decline in the disease resulting from implementation of a new vaccination program. Where monitored, the incidence rate dropped by 85 percent within four years of vaccine introduction and fell to zero in the fifth year. The authors estimate that Hib vaccine in the Ugandan immunisation programme now prevents almost 30,000 cases of severe Hib disease and 5,000 child deaths (under five years) annually, equivalent to the successful control of measles in the country.
Funding for Hib vaccine is a major part of the GAVI Alliance's (formerly known as the Global Alliance for Vaccines and Immunisation) programme support to Uganda. With GAVI support, Uganda was able to introduce 16.5 million doses of Hib vaccines nationwide from 2002 to 2006. The government chose to use what is known as a pentavalent vaccine - a 5 in 1 injection that includes vaccines for Hib as well as diphtheria, pertussis, tetanus, and hepatitis B.
"GAVI welcomes these extremely positive results" said Dr Julian Lob-Levyt, Executive Secretary of the GAVI Alliance. "Thanks to the collaborative efforts of the Ugandan Ministry of Health, the WHO, UNICEF and other partners, we can applaud a true success in controlling this deadly disease that has too often claimed so many lives."
Uganda was one of the first GAVI-eligible countries to adopt Hib vaccine, preceding what is now a global trend. According to a recent report released by WHO, the Centers for Disease Control and Prevention and the Hib Initiative, between 2004 and 2007 the proportion of the 72 poorest countries eligible for GAVI support using or approved to use Hib vaccine increased from 18 percent to 65 percent. In November, the GAVI board approved additional funding for Hib vaccine, bringing the total number of countries with approved proposals to 44.
"This is excellent news for the future generations of Ugandan children. Uganda has been a frontrunner in the Africa region in adopting this life-saving vaccine. The leadership of early introducers such as Uganda, Kenya and The Gambia has strongly influenced the decisions of many other countries in the region to adopt Hib vaccine. Today, 83% of the GAVI-eligible countries in Africa have now included or will soon include Hib vaccine in their national immunization programmes" says Rana Hajjeh, Director of the Hib Initiative.
"We are proud of the results of this study. It's encouraging to know that these kinds of interventions in Uganda and elsewhere are making a significant contribution towards achieving the Millennium Development Goal of reducing mortality in children less than 5 years of age," says Dr Sam Zaramba, Director General of Uganda Ministry of Health "And GAVI's support was catalytic in allowing us to tackle this disease quickly and efficiently."
The Government of Uganda recently committed national resources to procure Hib vaccine for its infant immunisation programme, in line with the GAVI co-financing policy.
"The introduction of Hib vaccine has now completely changed the epidemiology of bacterial meningitis in Uganda, with elimination of meningitis due to Hib as a public health problem" says Dr Kekitiinwa Pediatrician at Mulago Hospital,in Kampala Uganda, co-author of the study. "High quality surveillance has allowed us to understand and monitor those trends to ensure the quality of the immunisation programme, improve collaboration between clinicians and laboratories and inform on drug susceptibility for the common organisms."
Although Hib vaccines for infants were first licensed in 1991 and have since been widely adopted in industrialised countries, they have not been used extensively in the developing world due to multiple barriers such as limited Hib disease awareness, uncertainty about the burden of disease and concerns about the financial and logistical implications of vaccine introduction. It took almost 15 years for the Hib vaccine to be introduced in developing countries after it was first licensed.
There are efforts underway to bridge this gap by reducing the number of years developing countries have to wait to benefit from new vaccines. In 2007, a pilot Advance Market Commitment (AMC) was announced, aiming at accelerating the introduction of new vaccines in poor countries. The Uganda results follow similar results found in Bangladesh, Kenya, Chile, the Gambia, the United Kingdom, and United States. These studies have all concluded that Hib vaccine cuts the incidence of disease by 88% or more within 3 to 5 years.
In July 2007, a study from Bangladesh showed that routine immunisation of infants with a Hib conjugate vaccine prevented over one third of life-threatening pneumonia cases and approximately 90% of Hib meningitis cases.
A Kenyan study in 2006 showed that the Hib vaccine cut the incidence of disease by 88% within 3 years. The authors say that vaccinating against the bacterium Haemophilus influenzae type b prevented approximately 3,370 Kenyan children from being hospitalised in 2005.
The authors say that prior studies have shown that for every child with Hib meningitis in developing countries, there may be 5 to 10 others with Hib-related pneumonia, which is also preventable by vaccination. To achieve results more quickly, the WHO position paper on Hib vaccine recommends that children at highest risk, those under 2 years of age, be offered immunization at the time of vaccine introduction.