The British government has ordered 40 million doses and the first batch of 800,000 doses is expected to be shipped from Belgium , where the vaccine is manufactured, in the next few days. They will serve to immunize 400,000 people (two doses per person).
The UK medicines regulator, the Medicines and Healthcare Products Regulatory Agency (MHRA), has also started an ongoing review of other vaccines in end-stage human trials, such as the AstraZeneca / Oxford vaccine and Moderna’s vaccine. If these also meet the efficacy and safety standards set by the agency, they will also be approved for mass distribution.
The most rapidly developed vaccine to date was the mumps vaccine, which took just four years from conception to commercialization. Covid-19 vaccines have broken that record by a wide margin, taking less than a year to develop. But that does not mean that inappropriate shortcuts have been taken.
The MHRA has carefully studied the records of the more than 40,000 participants from various backgrounds in the trials. The efficacy of the vaccine, that is, what capacity it showed to prevent symptomatic COVID-19 in the trials, is 95%, although that figure is expected to decrease slightly in real conditions. And there have been no serious side effects, although these will continue to be monitored as the vaccine is implemented.
Health workers are expected to receive the vaccine first, as they are one of the most vulnerable groups. In addition, British hospitals have the ultra-cold freezers necessary to store the vaccine, so logistically speaking, this is a good place to start.
Don’t throw away the mask yet
This is all great news and good reason to be optimistic about the future. But Peter Openshaw, professor of experimental medicine at Imperial College London, warns that it would be a “terrible mistake” to soften COVID-19 control measures at this time.
So don’t throw away your mask or run to hug your grandmother just yet. A report by The Royal Society , the world’s oldest independent scientific academy, says that the restrictions are likely to remain in place for a few months, perhaps even a year.
When you receive the COVID-19 vaccine, you should not expect immediate protection against infection. White blood cells known as B lymphocytes first need to detect the antigen in the vaccine and then generate specific antibodies against it. If you are exposed to the coronavirus, these antibodies stick to the virus and neutralize it.
The response of your immune system, generated by B lymphocytes, is known as the primary response and takes about two weeks to activate. Therefore, during the two weeks after the puncture, you are still at risk of becoming ill from covid-19.
Additionally, many covid-19 vaccines require two injections to ensure complete protection. And the interval between injections varies from 21 to 28 days. Therefore, it will take about six weeks after the first injection for the vaccine to provide complete protection against the disease.
We do not know if vaccines stop transmission
Although vaccines in late-stage trials appear to be very effective in preventing symptoms of COVID-19, we still cannot be sure that they prevent transmission of the virus.
To do this, we would need a vaccine that provides so-called sterilizing immunity. This is where immune cells can bind to the virus to prevent it from entering cells where it can begin to replicate. This means that even six weeks after receiving the first puncture, you could still be infected with the coronavirus, even if you do not get sick.
Studies of the preclinical phase of the Oxford vaccine found that rhesus macaques that were immunized with the vaccine were protected from severe symptoms and had no evidence of lung damage. But the coronavirus infection was still in the upper respiratory tract and their noses still had viruses. If the same is true of humans, it would suggest that while they will be protected from symptomatic disease, they could still spread the virus.
At this stage, we don’t know if the Pfizer or Moderna vaccines stop transmission, although hopefully further studies will clarify that.
Also, if you have been vaccinated, there is a small chance, at least one in twenty, that the vaccine will not protect you. So even if you’ve been vaccinated – and the vaccination campaign may not end until the summer of 2021 – you should still wear a mask, work from home if you can, and practice social distancing. As for hand hygiene, let’s try to keep it up: Viruses, probably including SARS-CoV-2, will always be with us.
Manal Mohammed, Lecturer, Medical Microbiology, University of Westminster
This article was originally published on The Conversation. Read the original.
