The research study published in Science shows that they have designed micro-capsules that degrade and release the vaccine or drug particles at different time points of 9, 20 and 41 days after being injected. These new micro-capsules resemble tiny coffee cups that can be filled with a drug or a vaccine and are sealed with a covering lid. The idea behind this technology is that one injection delivers as many micro-capsules required and each capsule is made up of a biocompatible, FDA-approved polymer that can be designed to degrade at precise predetermined times, thus releasing the fillings of the “cup”.
“We are really excited about this new technology,” said joint leader of the study, Professor Robert Langer of MIT. “It could fundamentally change the ways vaccines are given—potentially enabling childhood vaccines to be given in a single injection.” This could have a significant impact on patients, especially in the Global South where patient compliance can be particularly poor.
Scientists at MIT also designed capsules that disintegrate hundreds of days after they are injected
Mice studies showed that the encapsulated particles were released in sharp surges at 9 and 41 days with no prior leakage. Furthermore, they filled capsules with ovalbumin, a protein found in egg white, commonly used to experimentally stimulate an immune response. They found that the immune response was as strong as two conventional injections with double the dosage.
Scientists at MIT also designed capsules that disintegrate hundreds of days after they are injected. However, there is one hurdle in developing long-term vaccines based on such capsules. The researchers need to ensure that the confined drug or vaccine is stable at body temperature and varying pH levels in the body before they are discharged. Currently, these capsules are being tested with a range of drugs and vaccines, including the inactivated polio vaccine as well as new vaccines in development. Approaches to stabilise long-term vaccines are also underway.
Baseline vaccines administered after birth and the following booster shots can be challenging to keep track of especially in remote areas of countries like Pakistan. Health care workers often struggle to manage and keep track of vaccines delivered and the ones that are pending. With the micro-capsule, once the vaccines have been injected at birth there will be no urgency of keeping track of it and the booster shots will be released in the body in a timely fashion. However, there is still time before this technology is commercialised and many factors need to be curtailed locally before such technology can be employed on a large-scale in developing countries.
Currently, the Expanded Program of Immunisation and the Sindh health department have launched an android-based application Zindagi Mehfooz Digital Immunization Registry in Sindh that has been developed by Interactive Research and Development (IRD), with the Indus Health Network supporting implementation across the province. The team on the IRD vaccination program is led by Dr Subhash Chandir, IRD’s director of Child Health & Vaccines Program and faculty at the Harvard Medical School, and IRD founder Dr Aamir Khan. Dr Chandir recently told The News, “About three out of four children are under vaccinated in Sindh. The Zindagi Mehfooz Digital Immunisation Registry will change the landscape of child health by engaging parents for timely immunisations, systemising the vaccinator’s jobs by creating centralised immunisation records, reducing time spent on paper-based reporting and creating more time and opportunities for vaccinators to immunise children.”
Follow-up is a major reason why Pakistan lacks adequate vaccination cover especially in remote areas. But there are also many misconceptions that create suspicion and affect coverage. Militant groups had banned vaccinations in Fata and threatened polio staff. This derailed the WHO polio eradication programme as well. Polio is a highly infectious viral disease that can cause irreversible paralysis. However, there are vaccines that can prevent this from occurring. Yet, in 2014, Pakistan and Nigeria were the only ones with a polio endemic with 300 cases out of 369 still prevailing. According to the WHO in 2016, 72% of the people in Pakistan were vaccinated against polio with a global coverage of 85%. Polio has been eliminated from all countries except for Afghanistan, Pakistan and Nigeria. Polio-free countries have been infected by imported virus, and all countries – especially those experiencing conflict and instability – remain at risk.
Another reason for the spread of polio is parental refusals. As part of a collaboration between Harvard Opinion Research Program at the Harvard School of Public Health and UNICEF, researchers conducted a series of polls about the polio vaccine among 3,396 parents and other caregivers of children under the age of 5 in Pakistan. Results showed that even though very few parents had negative views about the vaccinators, they had limited trust in the vaccines itself, especially in Fata. Half of the parents in Fata (48%) had heard rumours that vaccines caused sterility which made them reluctant.
In addition to these difficulties, Pakistan has experienced planned but unannounced power cuts which affects vaccines as they tend to deteriorate in unstable temperatures and environments. This can render them ineffective. Sometimes polio cases are reported in people previously recorded as immunised which could be due to ineffective cold chain management and suboptimal conditions at which the vaccines are being stored.
Literacy, education, and economic status were among the other significant factors associated with anti-vaxxers and non-immunisation. A study was conducted in two highly affected areas in Pakistan in 2014. It showed positive attitudes towards polio immunization were significantly associated with tertiary education and urban locality. Residents of rural areas had lower knowledge about polio and the vaccine than city dwellers. The residents of Quetta division were also less knowledgeable than those of the Peshawar division. People in the study who had tertiary education were more knowledgeable about immunisation than relatively less educated respondents.
And so, for the three-day campaign scheduled in Fata this past week, Nov 20 to 22, one hopes that it successfully targets its one million children below the age of 5 years. It will also be followed by a short drive to administer the vaccine to those children who might have been missed out in earlier efforts.
The writer is a researcher at the University of Cambridge