A successful vaccine for Covid-19 is not enough to prevent the spread of the coronavirus and many challengers would have to be overcome to implement a successful vaccination program, a recent study warned.
A report from the Royal Society’s DELVE (Data Assessment and Learning for Viral Epidemics) initiative suggests that there are serious challenges in developing, evaluating, manufacturing and distributing the vaccine.
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Why haven’t scientists been able to develop the vaccine yet?
An effective vaccine stimulates immune responses that nullify the chances of transmission of the infection and reduce the risk and severity of the disease. It also ensures long-term protection so that people do not have to re-vaccinate frequently.
Currently, scientists have not been able to identify the immune responses of SARS-CoV-2 infection. They don’t even know if the infection has an immune response. Antibodies and T cells have been detected in those who have recovered from the virus, but it is unclear if it leads to protection against reinfection, according to the report.
Evaluation of potential vaccine candidates
More than 200 SARS-CoV-2 vaccine candidates are currently in development, with some in the later stages of clinical trials. Some of the candidates later in the trials, such as the Oxford / Astrazeneca candidate, have used ‘viral vectors’, where a part of the SARS-CoV-2 genetic code is inserted into another harmless virus via the which antibodies are processed. generated.
Others, like Moderna, have used an alternative design, where a viral genetic code is produced like an RNA vaccine, which also leads to the production of viral protein when it enters a cell, according to the report.
Although development of these candidates has accelerated, vaccines fail at a later level of testing many times due to poor immunogenicity, he added.
Challenges in the manufacture of a future vaccine
Once a vaccine is available, the choice of vaccination strategies should be staggered to match manufacturing capacity.
The Coalition for Epidemic Preparedness Innovations (CEPI) estimates that by 2021, a global annual capacity of between 2 and 4 billion doses could be available without disrupting existing vaccine supplies, with much of the capacity in India and China, according to the report.
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If immunity is short-lived and annual vaccine boosters are needed, the ability to extend coverage will be needed while maintaining immunity in existing recipients, he added.
The challenge of vaccine distribution
The vaccine supply chain consists of a series of transport and storage steps.
The supply of raw materials used for the manufacture of medicines and the distribution of the finished product could be interrupted due to the pandemic itself.
The supply chain will be disrupted in the event that borders are closed due to blockade, staff become ill, countries compete for shortages, or the medical system is overwhelmed. To facilitate transportation, manufacturers are working to improve the thermostability of potential vaccines to reduce the need for distribution at very low temperatures, according to the report.
Additional medical personnel will need to be trained to quickly immunize the population, he added.
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