Coronavirus: As studies show positive results, here’s all we know so far about COVID-19 vaccine candidates

Over 150 vaccine candidates are being developed all over the world for COVID-19.

Coronavirus vaccines: The Lancet Journal on Monday released two studies on potential vaccines for the novel coronavirus, which has wreaked havoc all over the world. According to the studies, the two vaccine candidates – one developed by CanSino Biologics in China and the other by Oxford University and AstraZeneca Plc – generated immune responses among the volunteers and did not cause any dangerous side effects. Apart from this, a different kind of COVID-19 vaccine being developed by US-based pharmaceutical giant Pfizer along with German BioNTech also showed positive results in the early clinical trials, according to a statement released by Pfizer on Monday.

Here is what we know so far about coronavirus vaccines.

Vaccines for COVID-19: Key developments so far

• The results of the early trials from the vaccines developed by Oxford University and by CanSino Biologics, both rely on the harmless versions of another virus or a viral vector. Using this vector, the genetic material from the novel coronavirus is delivered into the cells of the person to trigger their immune response. The trials of both the vaccine candidates tested their safety and also hinted at their potential efficacy, as per a report by news agency Reuters. The report added that the participants of both the studies complained of fever and pain at the site of the injection but no dangerous side effects had been reported. The report stated that usually, vaccines are developed using a weakened form of the virus, which would in turn trigger an immune response and hence, prevent infection. However, quick development of such vaccines is not easy. And while viral vector vaccines need not be frozen, their refrigeration is required.
• The pandemic, as per the Reuters report, has also led to the fast tracking of other types of vaccine technology. The vaccine candidate developed by Pfizer and BioNTech has triggered an immune response and has also been well tolerated, as per the results of the initial data from trial on 60 healthy volunteers in Germany. This vaccine candidate relies on a different platform – ribonucleic acid (RNA). RNA is the chemical messenger which contains instructions for the production of proteins in cells. Such vaccines instruct the cells to generate proteins mimicking the coronaviru surface, which is then seen as foreign invaders by the body. The body then learns to target these invaders by an immune response. The Reuters report added that while this vaccine technology has been around for long, no messenger RNA vaccine has been approved till date.
• The vaccine candidates against COVID-19 have so far been tested on a small number of people. However, the report stated that according to researchers, the measurements of immune system responses continued to be encouraging. However, not much is still known about the vaccines which are being developed, especially in terms of the staying power of the induced immune response, or effectiveness of such vaccines in older adults or specific groups of people who are more impacted by the disease due to their ethnicity, race or comorbidities. Other questions also crop up regarding these vaccines, like the amount of dosage required, or any other serious risks associated with the vaccine.
• Over 150 vaccine candidates are being developed all over the world for COVID-19. While a viral vector vaccine is being developed by Johnson & Johnson, which is expected to go into human trials this month, Moderna Inc last week announced that its experimental RNA vaccine against the disease had shown that it was safe and it also elicited immune responses in all of the 45 healthy volunteers during the early stages of its study. The large-scale testing for Moderna’s vaccine is expected to commence before the month ends.
• The studies published by the Lancet have led to a better pathway for these vaccines to begin much larger, randomised, controlled trials to determine the efficacy as well as the safety of these candidates. Oxford University and AstrZeneca’s vaccine candidate is undergoing late-stage trials in Brazil, South Africa and the UK, while plans are also being made to begin studies in the US. Since the prevalence of coronavirus in the US is higher, results would be quicker to accrue there. CanSino’s vaccine has been approved for use in the Chinese military, even as it is yet to undergo large-stage clinical trials, the Reuters report added. Apart from this, Pfizer and BioNTech said that they were expecting to start a large-scale trial later this month with around 30,000 subjects.