Activity 3: Evaluating and Developing New Vaccines

PI: Dr. Stephen P Luby

Pneumococcal and Haemophilus Influenza type B (HIB) Surveillance

FPI: Dr. Aliya Naheed

Streptococcus pneumoniae (pneumococcus) is a leading cause of childhood pneumonia worldwide. New, safe effective vaccines have been developed, but the burden of pneumococcus in Bangladesh is unclear. Hence, policy makers do not have adequate information to develop a better strategy to reduce childhood death due to pneumonia.

The Centre’s scientists have already shown that vaccines administered during childhood save lives and reduce illness. Keeping in mind the MDG on reducing child mortality, ICDDR,B found it necessary to carry out surveillance on prevalence of pneumococcal (SPN) and HIB diseases among children below five years of age. These two infectious diseases are vaccine-preventable illnesses for which effective vaccines exists.

Pneumococcus causes severe respiratory disease and meningitis, and is thought to be a leading cause of childhood death. Lack of information on pneumococcal diseases and the high, cost of vaccine remain a barrier for the introduction, acceptance, and use of this vaccine. Additionally difficulty of growth by culture or identifying pneumococcus in laboratories further attributed to the knowledge barrier. ICDDR,B scientists, the pneumococcal study group, is therefore conducting a surveillance of pneumonia, meningitis and other severe illnesses among children less than 5 years of age at seven hospitals in Bangladesh and at two community field sites of ICDDR,B—urban Kamalapur in Dhaka city and rural Mirzapur in the Tangail district. Through blood and CSF culture pneumococcal study group is also documenting other bacterial illnesses that require hospitalization and might even cause death in children.

With the support of GAVI’s Pneumococcal Initiative, we initially developed a network of seven hospitals to carry out the surveillance. Our network includes Dhaka Medical College and Hospital, Dhaka Shishu (Pediatric) Hospital, Sir Salimullah Medical College and Hospital, Chittagong Medical College and Hospital, Chittagong Maa Shishu O General Hospital, Shishu Sasthya Foundation Hospital and Kumudini Medical College and Hospital. To help us facilitate increased number of blood and CSF culture, we have taken support from the IHP to provide service charges to microbiology departments of five government hospitals in order to enhance their laboratory capacities to detect HIB and SPN bacteria from culture.

We also received supports from the IHP to organize Local Investigators’ Meeting every year to disseminate research findings with the local collaborators and other stakeholders. These results have increased appreciation of the hospital physicians and microbiologists about the burden of HIB and pneumococcal disease among the young children in Bangladesh, who require admission in tertiary care hospitals. Through the 3rd Local Investigator Meeting of ADIP Pneumococcal Project 2007, we shared our findings with the Director General of Health Services and Deputy Director of EPI. The dissemination exercise allowed us to inform the local collaborators about the future direction and potential positive impact of HIB and pneumococcal vaccine introduction in the EPI program in Bangladesh.

We look forward to continue the surveillance through the existing collaborations with government and non-government hospitals in order to generate essential data on pnenumococcal (SPN) and HIB, two vaccine-preventable diseases that kills so many children every year.

Collaborating Institutions:

• Dhaka Medical College and Hospital
• Dhaka Shishu (Pediatric) Hospital
• Sir Salimullah Medical College and Hospital
• Chittagong Medical College and Hospital
• Chittagong Maa Shishu O General Hospital
• Shishu Sasthya Foundation Hospital
• Kumudini Medical College and Hospital

Results:

• The distribution of serotypes suggests that the majority of cases of invasive pneumococcal infections in Bangladesh could be prevented using vaccines under development.
• All 7 collaborating hospitals are now isolating S. pneumoniae in their laboratories due in large part to capacity building component of this project.
• This project has demonstrated that pneumococcus was an important pathogen to cause hospitalization among young children in Bangladesh.

Rotavirus Testing

FPI: Dr. Tasnim Azim

The results from this study set the backdrop for introduction of Rotavirus vaccine in Bangladesh and gives evidence about which strains are currently circulating.

Results:

We tested a total of 3608 stool specimens from diarrhea patients attending an urban (Dhaka) and three rural hospitals (Matlab, Bakerganj and Mathbaria) in Bangladesh between May 2005 and June 2006 for group A rotavirus antigens by using ELISA. Among them 868 (24.0%) were positive for group A rotaviruses. A more detailed study of the G and P genotyping was undertaken for a subset 118 rotavirus positive samples by RT-PCR and sequencing methods. An enormous diversity in the rotavirus strains circulating in both settings was found. During the current rotavirus season (2005-2006), a major proportion (51.7%) of the circulating strains was found to be G2P [4] strains. Other common strains isolated in our study were G1P [8] (17.8%) and G9P[8] (12.7%). Some uncommon strains (G12 and G11) were also detected during this period. Surprisingly G4 strains which were one of the predominant rotavirus strains in Bangladesh were nearly eliminated in 2005-2006 rotavirus season (only one G4 strain was detected). The non-P [8] rotavirus strains constituted 61.9% of the circulating strains in Bangladesh during 2005-2006.