Use of surveillance in vaccine decision-making

Pneumonia and diarrhoea are leading causes of childhood death, accounting for 24% (1.4 million) of global under-five deaths in 2015. A large proportion of pneumonia cases are caused by Streptococcus pneumoniae (pneumococcus) and diarrhoea cases by Rotavirus. Pneumococcus, along with other pathogens like Haemophilus influenzae type b (Hib) can lead to other clinical diseases such as meningitis and sepsis. Disease caused by pneumococcus, Hib and Rotavirus are vaccine preventable.

Three case studies were conducted to evaluate the importance of the Global Invasive Bacterial Vaccine-Preventable Disease (IB-VPD) Surveillance Network (GISN) and the Global Rotavirus Surveillance Network (GRSN) in vaccine decision-making in Bangladesh, Armenia and the Gambia by Alvira Z. Hasan, Senjuti Saha, Samir K. Saha, Gayane Sahakyan, Svetlana Grigoryan, Jason M. Mwenda, Martin Antonio, Maria D. Knoll, Fatima Serhan, Adam L. Cohen, for the Pneumococcal and rotavirus surveillance case study group. The study has recently been published in the journal 'Vaccine'.

These countries were included in the study because all conduct high quality surveillance as they meet highest performance criteria as determined by WHO.

Bangladesh is a lower-middle income country in the WHO South East Asian Region. In Bangladesh, there were about 15% deaths due to pneumonia, 15% deaths due to sepsis or meningitis and 6% deaths due diarrhoeal disease among children under five years in 2015 Bangladesh is a Gavi-eligible country and has entered the preparatory transition phase as of 2017.

The country will next enter the accelerated transition phase and in 5 years should reach fully self-financing status and lose Gavi support. Bangladesh has received Gavi support for the introduction of the pentavalent vaccine (which contains Hib, diphtheria, pertussis, tetanus and Hepatitis B) (in 2009) and PCV (in 2015) among other vaccines. The country has already applied for Gavi support for the rotavirus vaccine and is expected to introduce the vaccine in 2018.

Asia has major gaps in knowledge of the burden of Hib and pneumococcal disease and Hib vaccine and PCV impact data. However, Bangladesh is an exception in the region. Surveillance was used to show the dramatic impact of Hib vaccine, which was introduced in the country in 2009.

A study using data from 2 surveillance hospitals in Dhaka showed reduction in confirmed Hib meningitis cases from 92 to 12 cases per 100,000 within 1 year of vaccine introduction. This study suggested that the Hib vaccine prevented about 14,000 cases of Hib meningitis among infants in the country one year after Hib introduction.

Bangladesh has also used surveillance data to inform decisions regarding selection of the most appropriate pneumococcal vaccines. Bangladesh's Gavi application for PCV10 cited results from surveillance data, which showed high invasive pneumococcal disease (IPD) burden in young age groups and that a large proportion of disease was caused by the serotypes in PCV10.

Sentinel surveillance for pneumococcus and rotavirus, although a challenging activity to sustain, is critical in informing vaccine introduction decisions, monitoring vaccine impact, assessing cost-effectiveness of vaccine introduction, measuring shifts in disease, and monitoring resurgence of disease.

Written documentation of the processes and use of surveillance in vaccine decision-making can help inform policy-makers in new vaccine introduction and monitoring immunisation programmes and effectiveness of the vaccines introduced.