The early adoption of Coronavirus vaccines which showed moderate effectiveness could disrupt efforts to test and create improved versions of it, since the vaccination against the COVID-19 will not be going to be a simple business of eliminating the virus once the first vaccine becomes available, warn scientists.
As per Professor Adam Finn of Bristol University, "The vaccines coming through fastest are the most experimental," and there is a possibility that they would not be that great and others, which are created using more tried-and-tested but slower methods, "might be better".
But according to him, it will be difficult to prove that point if lots of people have already been given the first shot. A vast number of people are required to demonstrate "which is best or if a different vaccine is more suitable for particular groups, like the elderly", he added.
Whether the vaccine will work or not, this confusion could cause setbacks in dealing with the Coronavirus pandemic. "We should be preparing to meet this challenge and work out ways to compare the effectiveness of early vaccines – but at present, we are not doing that well enough", said prof Finn.
Currently, around the world, there are over 190 COVID-19 vaccines that are under development that include the Oxford AstraZeneca vaccine and Pfizer's BNT162b2. The phase 3 trial results of these vaccines are expected in weeks or months. But when the first effective vaccine will be announced, there will be massive pressure to use it immediately and the first candidates will be healthcare workers, as well as people at higher risk of catching the SARS-CoV-2 infection. But for elderly people, who generally have weaker immune systems, caution will be required.
Last week Kanta Subbarao, a World Health Organization (WHO) director explained the problem while saying that "early vaccine trials are not likely to show how well these products work in these populations." She also explained that vaccines often work better in young and healthy adults and this is why they are enhanced with a higher dose to boost immunity for diseases such as flu. According to her "it is unclear how well clinical trials will assess effectiveness in those in minority ethnic communities."
It is expected that by Spring many COVID-19 vaccines may pass the trials without any mechanism being in place to determine which one is the most effective for different groups of people. As per Dr. Gregory Poland, director of the Vaccine Research Group at the Mayo Clinic, "The complexity and chaos and confusion that will happen in a few short months has hardly dawned on anybody."
Authorities will approve any vaccine with the ability to protect at least half of those people who received the shot. But the problem will appear when other vaccines come and it is not clear whether they will have better effects compared to the first licensed treatment or not.
Prof Finn said that if a vaccine becomes available that works, but not quite well, "it is almost worse than not having one at all because it gets in the way of getting a better vaccine. We need to be thinking about it to avoid that situation urgently."