Two potential vaccines to protect against the novel coronavirus – one from Oxford University and AstraZeneca Plc and the other from CanSino Biologics in China – induced immune responses in healthy volunteers without dangerous side effects, according to healthy studies published in The Lancet on Monday cause.
A third other type of vaccine from Pfizer Inc and German biotechnology BioNTech has also shown promise in a small, early study released on Monday and hopes that at least one will prove safe and effective.
The following are five insights from Monday's developments, some of which come from an editorial in The Lancet Medical Journal:
1. The Oxford / AstraZeneca and CanSino teams published results from early studies with COVID-19 vaccines that used harmless versions of another virus or virus vector to transport genetic material from the novel coronavirus into cells and generate an immune response . Both studies were primarily developed to test the safety of the vaccines and to give possible indications of their effectiveness. In both studies, subjects experienced mild side effects such as fever and injection site pain, but no serious adverse events were reported. Vaccines have traditionally been made using a weakened or inactivated form of the virus to elicit an immune response and prevent infection. However, these vaccines are not easy to develop quickly. Viral vector vaccines do not need to be frozen, although they need to be refrigerated. Johnson & Johnson's Ebola virus vaccine became the first viral vector vaccine approved in Europe on July 1st.
2. The COVID-19 pandemic has accelerated other new types of vaccine technologies. It was shown that the Pfizer and BioNTech candidate, who had first data from a German study of 60 healthy volunteers, triggered an immune response and was well tolerated. The data was consistent with another early-stage U.S. study released earlier this month. This vaccine uses another novel platform – ribonucleic acid (RNA) – the chemical messenger that contains instructions for cells to make proteins. RNA vaccines are designed to instruct cells to make proteins that mimic the surface of the coronavirus. This then sees the body as a foreign intruder and learns to aim with an immune response. Although the technology has been around for years, there has never been an approved messenger RNA vaccine.
3. The number of people in whom experimental COVID-19 vaccines have been tested is low. However, researchers say that measurements of immune system responses are encouraging. Much remains unknown about the COVID-19 vaccines under development, particularly about the stamina of any immune response and effectiveness in older adults or other specific groups, including people with chronic health problems and ethnic or racial groups who are more affected by the disease are affected. Other open questions are: Will a single dose be sufficient? Do they spur enough neutralizing antibodies and T cells, a type of white blood cell that helps the immune system destroy infections? Do T cell responses correlate with longer-term protection? Is there a way that a vaccine could be at risk of a more serious infection?
4. More than 150 possible vaccines to prevent COVID-19 are under development. J&J is also developing a viral vector vaccine against coronavirus and expects human trials to begin this month. Moderna Inc said last week that its experimental RNA vaccine against COVID-19 had shown in an ongoing early-stage study that it was safe and produced immune responses in all 45 healthy volunteers. Moderna is expected to begin extensive testing before the end of July. Once vaccines have overcome early safety barriers, they need to be tested on thousands of subjects to ensure that they can be safely administered to millions or billions of healthy people.
5. The studies released on Monday are a good sign for those who are much larger and randomly controlled to assess their effectiveness and safety. AstraZeneca has carried out late stage studies in the UK, Brazil and South Africa and intends to start studies in the US where the prevalence of coronavirus is higher. In regions with high active infection rates, the results can be achieved much faster. Pascal Soriot, AstraZeneca's chief executive, said the company hopes the vaccine will be available this year, depending on how quickly late-stage studies can be completed as the virus becomes less common in the UK. While CanSino has not yet started large-scale clinical trials to determine how well its vaccine prevents infection, it has been approved for use by the Chinese military. Pfizer and BioNTech have announced that they will begin a study with up to 30,000 subjects later this month to demonstrate the effectiveness of the vaccine.
(Except for the headline, this story was not edited by NDTV staff and published from a syndicated feed.)