Covid19 vaccine

Research on vaccines for the severe acute respiratory syndrome (SARS) and Middle East Respiratory Syndrome (MERS) viruses paved the way for more rapid development of a SARS-CoV-2 (Covid-19|) vaccine allowing candidate vaccines to reach clinical trial stages in record time. Global collaboration and diversion of funding have contributed to the speed of vaccine development.

Pfizer and Moderna last month reported preliminary results from late-stage trials, showing that their vaccine candidates were almost 95% effective against the virus. Oxford University and AstraZeneca also said that its Covid-19 vaccine could be up to 90% effective in preventing the disease.

Development and testing vaccines has been accelerated

This is good news as previously experts had warned that it could take up 12 to 18 months for a vaccine to be available. “The process of development and testing of vaccines against COVID-19 has been accelerated with unprecedented speed. Vaccine development has previously been considered to take at least 10 years, from discovery research and pre-clinical stages followed by phase 1 to 3 clinical trials and finally regulatory review and approval.

“Historically, despite the investigation of many candidate vaccines against infectious diseases, and especially novel emerging viruses, very few reach clinical trial stages. This is frequently due to lack of adequate funding and a large enough market to incentivise manufacture allowing the vaccines to be economically viable,” says Professor Felicity Burt, an expert in arbovirology in the Division of Virology from the University of the Free State (UFS).

According to her, the development of a vaccine against Ebola virus is a classic example of vaccine development being shelved after the discovery and pre-clinical trials, until the 2014 outbreak. Ebola virus was first identified in 1976 as a cause of severe haemorrhagic fever with fatality rates exceeding 80% during some outbreaks.

The impact on developing vaccines for other viruses

Burt, who currently holds a NRF-DST South African Research Chair in vector-borne and zoonotic diseases, says several vaccines currently under development for Covid-19 are based on new technologies that have previously been used in the discovery phase of vaccines. The diversity of platforms under investigation should provide us with a diverse range of vaccine formulations. This could be beneficial as some may be more suited for selected populations such as the elderly. In addition, the ability to scale up manufacture and the stability of the end product will be important for global distribution.

“The use of next-generation technology allows flexibility in terms of being able to manipulate or modify the antigen used for inducing protective immunity and will allow the vaccines to be modified to accommodate any change in antigenicity if required.

“The knowledge acquired on safety and efficacy of the various vaccine platforms emulating from the Covid-19 trials can only enhance future vaccine development against other infectious pathogens, paving the way for use of diverse platforms with a ‘plug and play’ approach, platforms in which antigens can be readily replaced to tackle novel emerging pathogens,” says Burt.

Source: University of the Free State /