News from the UK is that the Oxford University/AstraZeneca vaccine appears to be at least 70% effective:
“The announcement today takes us another step closer to the time when we can use vaccines to bring an end to the devastation caused by [the virus],” said the vaccine’s architect, Prof Sarah Gilbert.”https://www.bbc.com/news/health-55040635
That is good news that comes shortly after the announcement from the US that the Pfizer/BioNTech vaccine could be 90% effective:
“The developers – Pfizer and BioNTech – described it as a “great day for science and humanity”.https://www.bbc.com/news/health-54873105
Their vaccine has been tested on 43,500 people in six countries and no safety concerns have been raised.”
What is doubly good is these two vaccines have been developed using completely different principles and work in quite different ways. There are disadvantages to both but in ways that are distinctly different.
As I understand it, the Oxford vaccine uses a different virus (one that causes colds in chimps) to deliver a key protein from the covid coronavirus to provoke our immune system into creating the needed antibodies. A similar vaccine is also under development in Russia and is also showing success https://www.bbc.com/news/health-54905330
The Pfizer/BioNTech vaccine and a similar one being developed by Moderna ( https://www.bbc.com/news/health-54902908 ) uses a more novel technique, exploiting messenger RNA. The use of mRNA potentially opens up faster and more adaptable vaccine development in general.
“Vaccines train the immune system to recognize the disease-causing part of a virus. Vaccines traditionally contain either weakened viruses or purified signature proteins of the virus.https://theconversation.com/how-mrna-vaccines-from-pfizer-and-moderna-work-why-theyre-a-breakthrough-and-why-they-need-to-be-kept-so-cold-150238
But an mRNA vaccine is different, because rather than having the viral protein injected, a person receives genetic material – mRNA – that encodes the viral protein. When these genetic instructions are injected into the upper arm, the muscle cells translate them to make the viral protein directly in the body.
This approach mimics what the SARS-CoV-2 does in nature – but the vaccine mRNA codes only for the critical fragment of the viral protein. This gives the immune system a preview of what the real virus looks like without causing disease. This preview gives the immune system time to design powerful antibodies that can neutralize the real virus if the individual is ever infected.”
An added advantage for the mRNA vaccines is that it can be produced without a biological step. Apparently the challenge for mRNA vaccine development has been finding ways of keeping the mRNA sufficiently stable that vaccines can be produced en-masse. While those hurdles have been overcome, the Pfizer/BioNTech vaccine has to be stored at very cold temperatures and degrades within days even at normal fridge temperatures.
The Oxford/AstraZeneca vaccine is more conventional and much easier to store. It is also easier to manufacture as it uses existing processes and will be much cheaper than the mRNA based vaccines.
Meanwhile, there are multiple other vaccines for covid-19 under development. This table from a PubMed article in June, has a good overview of the variety of types of vaccines under development. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7301825/table/t0005/?report=objectonly