The FTSE 100 firm revealed on Monday that its jab, AZD1222, has an average efficacy of 70%.
That’s because when volunteers were given a half dose followed by a full dose at least one month apart, the chance of being protected from the virus was 90%, which fell to 62% when administered as two full doses at least one month apart.
The news pushed AstraZeneca down a notch on Monday, since it did not match the higher results achieved by Moderna and Pfizer, which flagged efficacy of 94.5% and 90% respectively.
Neil Wilson, analyst at Markets.com, argues that the Oxford vaccine is still likely to play a big role in global immunisation because it is cheaper and easier to transport.
In fact, a full course is expected to cost £6, compared with £30 and £38-45 for Pfizer and Moderna’s candidates, respectively.
The fact that one dose and a half is more effective than two is also expected to be a benefit when it comes to distribution.
Analysts at finnCap PLC (LON:FCAP) noted that AstraZeneca’s goal to produce up to 3bn doses in 2021, is more than the number available for the Pfizer and Moderna vaccine combined.
To freeze or not to freeze
Moreover, the jab can be stored, transported and handled at normal refrigerated conditions (2-8°C) for at least six months and administered within existing healthcare settings.
Moderna’s mRNA-1273, instead, remains stable at the same temperature for 30 days, but needs to be stored at -20° C for a longer duration of up to six months.
Conversely, Pfizer’s jab BNT162b2 not only must be stored at ultra-cold storage, between -60°C and -80°C, at all times.
“Whereas this is a challenge in developed countries, some have argued that it could be almost impossible in some parts of the developing world,” Adam Barker, analyst at Shore Capital, commented.
“In response, Pfizer is establishing its own supply chain and plans to distribute the product direct to vaccination sites (avoiding wholesalers) in specially designed cooler boxes.”
These allow the vaccine to be maintained for ten days, and once removed from its container, it can survive for around a day at temperatures of 2-8°C.
However, the product is so sensitive to temperature that there are recommendations on how often the box should be opened and it survives for just two hours at room temperature.
“Suffice to say, most facilities (e.g. GP surgeries, pharmacies) don’t have the freezers required to store the vaccine at such low temperatures and shipping in large quantities of dry ice to keep re-icing the containers isn’t necessarily simple either,” Barker added.
“Even though the establishment of the supply chain necessary to distribute Pfizer/BioNTech’s vaccine clearly isn’t impossible to achieve, it is going to be challenging and will require a great deal of coordination at vaccination sites.”
mRNA vs DNA
BNT162b2 and mRNA-1273 need to be stored at colder temperatures because, as the name suggests, they are based on mRNA technology.
Driving the process is messenger RNA, or mRNA, which plays a fundamental role in human biology by transferring the instructions stored in DNA to make the proteins required in every living cell.
Medicines based on mRNA instruct a patient’s own cells to produce proteins that could prevent, treat or cure disease.
AstraZeneca, instead, has gone down the traditional use of inactivating the virus: by providing the body’s defence mechanisms with advanced warning of the virus, the inoculation triggers production of the antibodies required to fight the real thing when it is contracted.
Researchers used the copy of a chimpanzee viral vector based on a weakened version of a common cold virus, because it causes infections in the animals and contains the genetic material of the SARS-CoV-2 virus spike protein, at the basis of COVID-19.
After vaccination, the surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus if it later infects the body.
To be extra safe, the UK government has pre-ordered enough vaccines to immunise the whole population over five times, including 100mln of the Oxford vaccine, 4mln of which are ready immediately, 40mln of Pfizer’s and 5mln of Moderna’s.
Earlier this month, the Department of Health said it had invested over £230mln for manufacturing capacity while “an enormous amount of planning and preparation has taken place” for the rollout, to ensure adequate provision, transport, PPE and logistical expertise.
The light at the end of the tunnel
According to Deutsche Bank, the recent positive news on vaccines mean that by spring things should be looking much closer to normal.
“We are now on track for the majority of the developed world to immunise its vulnerable population to COVID by the spring and the entire population by mid-year,” analysts said.
“The combined vaccine news of the last few weeks is an unprecedented victory for science that will lead to a much faster pace of normalisation to our daily lives compared to what we would have assumed just a few weeks ago.”
On Monday afternoon, shares in AstraZeneca were trading 3% lower at 8,039p, while Pfizer shed 1% to US$36.49 and Moderna shot up 4% to US$101.46.