Demystifying Covid-19 vaccine development
Monday, October 5th, 2020
The multi-layered process has come under scrutiny, especially with the unprecedented speed at which experts are developing new jab to deal with the pandemic.
Evelyn Makena @evemake_g
Vaccination is among the greatest modern medicine interventions saving up to three million lives every year according to World Health Organisation.
Such background has seen researchers and scientists around the world make concerted efforts to develop a vaccine against the novel coronavirus disease, which emerged in China late last year.
As the disease has spread across the world, scientists are under intense pressure to craft a safe and effective vaccine to contain the pandemic.
Vaccines contain dead or weakened part of viruses or disease-causing organisms and are administered before exposure to an infection to stimulate the immune system to develop antibodies.
Abdalah Ziraba, epidemiologist, African Population and Health Research Center (APHRC), says vaccines ordinarily take even up to 15 years to develop.
However due to the urgency of responding to the pandemic, scientists are racing against time to develop coronavirus vaccine within the shortest time possible.
“We are living in abnormal times. The world has not experienced many pandemics of such magnitudes thus the urgency in Covid-19 vaccine development,” he says.
Presently there are over 170 candidate vaccines tracked by WHO across the world with the global health body noting that the earliest widespread vaccinations are expected to take place in mid-2021.
Overall, Ziraba notes that the process of coming up with a vaccine, entails several stages that involve work on the actual development of the vaccine and efforts to test it for safety and effectiveness.
“A lot of work goes in the actual development of a vaccine and in clinical trials to test whether the proposed agent for a vaccine has the desired effects,” he says.
Clinical trials involve four stages that are both time-consuming and resource intense.
At the pre-clinical trial stage, researchers test the vaccines on animals such as monkeys to see if it triggers an immune response.
This is followed by phase one of the clinical trial, where vaccine is tested on humans with participants ranging between 20 and 100.
“This phase tests for the human safety of the vaccine,” adds Ziraba.
If successful, clinical trials proceed to phase two, which tests the vaccine on a higher population, usually over 100 people to determine the most effective mode of administration, either oral or injection.
Vaccines that reach this stage and are successful get clearance by a regulatory body to proceed to phase three.
The final stage of the clinical trials involves testing the vaccine on large number of participants, usually in thousands in multiple sites to confirm its safety, evaluate side effects and effectiveness.
Trials on phase three involve an experimental and a control group given a placebo in order to draw comparison.
The experimental group is given a vaccine with an active agent while the placebo receives an inactive agent.
“This final phase of clinical trials takes time because there could be unanticipated side-effects that manifest with time and because of the need for a larger sample population,” explains Ziraba.
Additionally the process could delay because of need to ascertain vaccine safety and follow relevant ethical procedures.
Once success of phase three is confirmed, scientists are given a green light to take the vaccine to market.
Of all the candidate vaccines being tracked by the WHO, only nine are in phase three, with the majority, 142, still at pre-clinical trial stage.
So far, no vaccine is being developed in Africa: the majority is in Europe and America. Similarly, there are only two vaccine clinical trial sites on the continent, both in South Africa.
There are ongoing efforts by Oxford University to conduct a clinical trial in Kenya and Uganda aims to start a vaccine trial in December 2020 in collaboration with the Imperial College, London.
This low number of clinical trials on the continent could slow the rate at which Africa will access approved vaccines, notes, Catherine Kyobutungi, Executive Director, APHRC.
“Lack of participation makes it difficult to access vaccines because of the global scramble.
Secondly, there is need to test vaccines in Africa to check for efficacy and safety on the African population,” she says.
If vaccines are tested on other continents with a predominant Caucasian population, African countries will still have to conduct tests to check for safety and compatibility in a process that could take up to nine months.
Participation in trials can improve access to vaccines, and ethical procedures of trials give room for participants to access vaccine once it is available, says Catherine.
Once the vaccine is made available, the next headache would be to ensure its equitable distribution.
In the ideal world, Gershim Asiki, a research scientist at APHRC says, the priority of access should be most vulnerable populations.
“Distribution process involves moving the vaccine from the manufacturer to the last mile,” he says.
After the vaccine is approved, its then produced in enough quantities for universal coverage.
The process is followed by approval by an international governing body that determine which countries need the vaccine the most, based on disease prevalence, severity and other aspects.
But before countries can receive the vaccines, they must conduct regulatory approvals to ensure the product is safe for their populations.
Timely transportation of vaccines is vital to ensure it maintains its potency until it gets to the users.
“Most vaccines remain potent between -4 and -8 degrees Celsius and this needs to be maintained until the last person gets the vaccines,” Asiki adds.
Usually health workers, the elderly and those with comorbidities should be prioritised.
However, based on previous pandemics, what happens in the real world is completely different.
“Priority is given to the highest bidder as opposed to the most vulnerable populations,” he notes.
The scenario of skewed vaccines distribution played out during the outbreak of the swine flu in 2009.
Low income, countries such as Mexico that were adversely affected by the pandemic suffered vaccines shortages since developed nations had placed large advance orders of the doses.
Even with Covid-19 vaccine, developed nations have begun the process of getting into contractual agreements with pharmaceutical companies to secure a certain amount of doses.
Through an initiative dubbed Operation Warp Speed, the US aims to deliver 300 million doses to its people by January 2021.
It has invested money in excess of trillions of shillings on pharmaceuticals such as Johnson & Johnson and AstraZeneca, both of which are developing Covid-19 vaccines.
To avoid vaccine shortages similar to those in past pandemics, a scheme named COVAX has been created to promote equitable access to low income countries.
The initiative by WHO and the Vaccine Alliance (GAVI) is working to raise funds to make two billion of effective vaccine doses available by late 2021.
“The idea behind COVAX is to invest in different vaccines being developed and ensure early access to poorer nations.
It is working to raise funding and reach contractual agreements with manufacturers to secure vaccines for low middle income countries to cover at least 20 per cent of populations at risk,” says Gershim.
Under the initiative, 950 million doses will be distributed to lower income nations and 100 million to humanitarian situations.
So far, the scheme is engaging governments from 92 nations to make a contribution towards the initiative and also calling on high income countries to offer financial support to bolster the efforts.
These efforts, Gershim notes, are not enough to guarantee universal access to the vaccine hence the need for African governments to invest in more initiatives.