Pneumococcal vaccine developed by the Pune-based Serum Institute of India has been pre-qualified by the World Health Organisation (WHO) in the third week of December 2019. The prequalification of the vaccine by WHO was based on the results of a phase-3 trial (the final phase of human clinical trial) carried out in 2,250 children in Gambia, a small West African country.
According to a November 2019 UNICEF report, pneumonia caused 1,27,000 deaths in India in 2018, the second highest number of child mortality under the age of five in the world. In India, pneumonia and diarrhoea cause the most deaths in children under five years.
The pneumococcal vaccine PNEUMOSIL is a conjugate vaccine to help produce stronger immune response to a weak antigen. Serum Institute had optimised an efficient conjugate vaccine manufacturing processes for its meningitis A vaccine (MenAfriVac), which was used for manufacturing the pneumococcal vaccine. This helped the company reduce the manufacturing cost of pneumococcal vaccine.
Low cost vaccine
“We intent making the vaccine available to low- and middle-income countries for about $2 per dose, while countries pay nearly $3 when the vaccine is co-funded by Gavi,” says Dr. Rajeev Dhere, Executive Director of Serum Institute. “This will make the vaccine 30% cheaper than the Gavi price and dramatically lower for countries that do not get the vaccines through Gavi.”
The company already has a licence to manufacture and export the vaccine. The company has just completed the phase-3 trial in India and will soon be submitting the data to the Drugs Controller General of India (DCGI) for licensing.
In 2017, pneumococcal conjugate vaccine was included in the under India’s Universal Immunisation Programme (UIP). It has been introduced in a phased manner starting with Himachal Pradesh, parts of Bihar, Uttar Pradesh, Madhya Pradesh and Rajasthan. A vaccine manufactured by a multinational company is being used for immunisation.
The efficacy of the Serum vaccine was tested against an already approved pneumococcal vaccine (Synflorix). In the Gambia trial, three doses of the vaccine were given to 2,250 infants at 6, 10, and 14 weeks and a booster dose was given to 675 infants at nine months age. “The efficacy of our vaccine was comparable with the existing approved vaccine tested during the trial,” says Dr. Dhere. “It was based on the clinical trial data that the WHO prequalified the vaccine.”
Offers wider protection
There are about 90 serotypes of pneumonia-causing bacteria ( Streptococcus pneumoniae ). The disease serotypes vary from one region to another. The 10 serotypes that are widely prevalent and responsible for causing pneumonia in Latin America, Africa and Asia, including India have been chosen for Serum’s pneumococcal vaccine so that the vaccine confers greater protection.
Compared with existing 10-valent vaccine, Serum’s vaccine contains two serotypes that are present in 13-valent pneumococcal vaccine. “The two serotypes present in the 13-valent vaccine have been included in our 10-valent vaccine to offer wider coverage of serotypes seen in Africa and Asia,” says Dr. Dhere. This makes Serum’s pneumococcal vaccine better than the currently available 10-valent vaccine.
Phase-1 and phase-2 trials were earlier carried out in India. A phase-3 trial on 600 infants carried out in different places in India has just been completed. The trial tested the efficacy of the vaccine when given at 6, 10, and 14 weeks without a booster dose. “Since the phase-3 trial data from Gambia were already available before the trial could begin in India, the DCGI permitted the trial to be carried out on fewer children and without the booster dose,” says Dr. Dhere. The trial was carried in collaboration with PATH with funding from the Bill & Melinda Gates Foundation.
Currently, Serum is conducting another trial in Gambia and India where the vaccine is given at 6 and 10 weeks and a booster dose at nine months of age. Using the two primary dose and a booster dose will help reduce the cost of immunisation. The two primary and booster dose schedule provides almost the same immune response as the three primary and a booster dose schedule.
“The three primary doses coincide with the pentavalent immunisation schedule, while the booster dose at nine months coincides with the first dose of measles vaccine,” says Dr. Dhere.