Within a few months after it broke out in Wuhan, China, last December, the new coronavirus the causes Covid-19 had spread almost all over the world. Then on January 30, the World Health Organization (WHO) director-general, following the recommendations of its emergency committee, declared Covid-19 a public health emergency of international concern (PHEIC).
The world would be plunged into a desperate race against time in search of a vaccine against the virus, which has infected more than 12 million people and killed more than 545,000 worldwide. World scientists then agreed to speed up research especially to get a vaccine to help contain the spread of the pandemic and facilitate care for those affected.
It is encouraging that the global community has mobilised resources around vaccine work for Covid-19 and scientists seeking treatments and vaccines but neither is yet to be found.
A vaccine trains the immune system to recognise and attack the virus when it encounters it. A vaccine, therefore, stimulates the body to raise an immune response before you get infected with a pathogen, so that your body recognises infection with the pathogen when it enters your body and neutralises it. As a result, you either become immune to the disease or suffer fewer consequences of it.
Vaccines protect both the person who is vaccinated and the community. Viruses cannot infect someone who is vaccinated; as such, they cannot pass the virus to others — which is known as “herd immunity”.
Not only would a vaccine save lives but also protect people against the disease. For instance, Kenya would not have lost 143 lives nor 8,250 persons infected with the virus by July 7 if a vaccine was available. Besides, a vaccine would obviate the social distancing restrictions most of us now live under and ease the economic lockdown.
A vaccine would also protect health workers and slow down the negative effects of Covid-19.
The WHO has listed more than 140 vaccine candidates, which are in various stages of pre-clinical trial phases. The initiatives are led by leading scientists from the academic sector, some of the largest private pharmaceutical firms and small biotech companies.
Many are working on antiviral drugs, some of which are in use against other illnesses, to treat Covid-19 patients. Others are working on vaccines that could be used to prevent the disease.
It could take several months before treatments that are proven to be effective against Covid-19 are available — even longer for a vaccine. Some of the earliest treatments are likely to be drugs already approved for other conditions or have been tested on other viruses.
It takes long to develop a vaccine. After laboratory and animal testing, it has to pass through several clinical trial stages before being approved for widespread use in people.
Trials are organised in phases with the first and second typically testing the safety of the drug. The drug then enters Phase III, where its efficacy is tested. That can take 10-20 years. Regulatory review and approvals can take two years.
Owing to the rigorous process, less than 10 per cent of experimental vaccines ever become commercial products. It is also difficult to speed up things since scientists have to enroll enough people at every stage to get useful results. They also have to wait long enough to see whether the drug has harmful side-effects.
Developing a vaccine is also a costly enterprise; it costs $200-500 million to develop one.
We should not lower our guard, nonetheless. With confirmed Covid-19 cases past 6.4 million and growing exponentially, we are not out of the woods yet. To remain safe, and yet there is no drug in sight, we have to rely on social distancing, contact tracing, self-isolation and keenly following other expert safety guidelines.
No study exists to show that there are particularly people or groups that are immune to the virus. Indeed, what has been shown is that people of all ages, gender and race can get it. Let us be vigilant because we are all equally susceptible to the virus.
Prof Kiptoo, professor of immunology, is the CEO of Kenya Medical Training College (KMTC). [email protected]