This post by a well respected Tayside consultant working on covid wards really helped put all the last niggles at rest
It's long but worth a read
The COVID vaccines are very nearly with us, the roll out of vaccination is due to start within weeks in the UK. This has led to a lot of people asking me whether they should have the vaccine; is it safe, given how quickly it’s been developed; will it work; how long will it work for; and is it even necessary. Here are my thoughts:
Should I have the vaccine?
Unless you are allergic to the content of the vaccine, I strongly urge you to have the COVID-19 vaccine when it becomes available. This is a disease that we cannot prevent, we have very limited ability to treat it (effectively only 1 drug shown to have any meaningful benefit - Remdesevir may not be as useful as first thought https://www.bmj.com/content/bmj/370/bmj.m3379.full.pdf and convalescent plasma makes no difference to outcomes at 30 days https://www.nejm.org/doi/full/10.1056/NEJMoa2031304?query-featured_coronavirus= ), has a frighteningly high mortality in older people (between 8 and 16% in people over 80 in wave 1), and is not going to disappear. Look back at the diseases that have been eradicated, or brought down to very small case numbers, in the last 50 years due to vaccinations – polio, measles, smallpox, diphtheria, lockjaw (tetanus) – and the more recent successes in vaccination programs – Human Papilloma Virus (a major cause of cervical cancer), varicella zoster virus (shingles). We have no effective treatments for the majority of these diseases, and vaccination has been the answer. COVID is no different.
Is it safe, given how quickly it has been developed?
Though the two available forms of vaccine (mRNA and simian adenovirus) have been made available less than a year after the discovery of SARS-CoV-2, the work to devise these vaccines has been going on for decades. Researchers have been working on a SARS-CoV-1 and MERS vaccine since they were discovered in the naughties. There is similarity between all three viruses, so when developing a vaccine for SARS-CoV-2 they had a huge head-start on the program. The mRNA vaccine program has been in development since the late 90s. mRNA vaccines have been proposed, and tested against parasitic infections, with very encouraging results – parasitic infections are not well funded, so this research has moved very slowly, but COVID has provided a well needed focus of funding to these teams, hence the rapid progress made. The processes used to make these vaccines are well described by the manufacturers in the initial publications.
These vaccines have had rapidly accelerated pathways because of the enormous clinical need, a huge push of funding to meet that clinical need, and an unprecedented collaborative effort between basic scientists, clinicians, Pharma, and people who volunteered to have the vaccine in the trials.
Some quick myth-busting:
· The mRNA vaccine does not, and cannot, alter anyone’s DNA. This is not now it works. “Gene therapy” (Trying to alter host DNA by ingesting, inhaling, or injecting strands of DNA) has been tried, and it doesn’t work. This is mRNA, not DNA. mRNA is the messenger code to make a protein, in this case the SAR-COV-2 spike protein, so that the body can generate an immune response to the protein without injecting the virus.
· The mRNA virus is put into nanoparticles, not nano-bots. Nanoparticles are very small balls of lipid that can pass through cell membranes to deliver the mRNA to the ribosomes. They need to be kept at very low temperatures, so the vaccines have to be stored at -70 degrees C. This is nano-technology, not nano-robotics.
· The simian adenovirus vaccine has the SARS-CoV-2 spike protein added to it, so when the (dead) simian adenovirus is injected, the immune system makes a response to the spike protein. A simian adenovirus is used because humans have no previous immunity to them, so they won’t be destroyed before there’s a chance to generate a response to the spike protein, which may happen with a human adenovirus.
· The simian adenovirus is not from a monkey, it’s a virus that infects monkeys.
· There is no foetal tissue in the vaccines. Cell lines that have been cultured from foetal tissue from decades ago have been used in the development of vaccines. Some vaccines are tested on these cell lines, to determine the effect on human cells. Some vaccines are grown on these cell lines, then the vaccine is purified to remove the human cell lines from the vaccine. These cell lines are cloned from the original cells harvested decades ago – they are a ‘photocopy’ of a ‘photocopy’ of a ‘photocopy’ of etc. (Fact check here: https://uk.reuters.com/article/uk-factcheck-vaccine/fact-check-lung-tissue-of-an-aborted-male-foetus-is-not-in-the-vaccine-for-coronavirus-idUSKBN27W2I7)
· There is no live SARS-CoV-2 in either of the vaccine types, they cannot cause COVID.
The vaccines have been tested in phase 1, 2 and 3 clinical trials. Side effect data is published – the side effects are minor, as seen with other vaccines, mainly injection site pain, cold/flu symptoms that are short lived. There is a special dispensation built into UK law to allow vaccines to be given to people before the full licensing process is complete – this clause was activated a number of months ago, to allow early access to the vaccine, following a public consultation.
Will it work?
We know that the vaccines generate both an antibody response, and a T-cell response, both are important in immunity against viruses. The phase 3 studies report between 70 and 95% effectiveness for the vaccines, and they work just as well in older people as younger people (which is not always the case). So, yes, they do seem to work.
How long will immunity last?
We simply don’t know, but the longer we go on the more optimistic we get. The very earliest infections are only 11 months ago. Some people still have antibodies 8 months after their infection, but there are reports of the levels falling in other people. Antibody levels fall when they’re not needed, and rise again when they are, so we need to know more about how the immune system reacts to the second, and third time someone comes into contact with SARS-CoV-2. Second infections are rare, though have been reported in very small numbers around the world. We get an annual flu vaccine because Influenza A undergoes antigenic drift, and occasionally antigenic shift – this is a form of mutation of the virus that happens every year (drift) and once every so often (shift, think swine flu and avian flu). SARS-CoV-2 has a number of different versions, but so far only the Danish variant (linked to mink farming) seems to be significantly different in its virulence. So we may only need 1 vaccination, or we may need it more often, we just don’t know yet.
Do we need to have it?
This is a great question.
The question of pre-existing immunity is particularly challenging. Assumptions were made at the start of the pandemic that no-one was immune, or even partially immune, to COVID-19, as SARS-CoV-2 was a completely novel virus. Evidence varies from anecdotal observations that patients in ICU in wave 1 tended not to have had their flu vaccine, to in depth analyses of blood from patients with and without COVID infection to look for cross reacting antibodies and T-cells, which were not found. More recently there are studies showing T-cell activation in blood from donors taken prior to 2020, and in patients who have negative COVID antibodies.
There is a very good discussion about this in the BMJ here https://www.bmj.com/content/bmj/370/bmj.m3563.full.pdf There are a lot of confounding factors in among all this, of course - we know that SARS-CoV-2 is highly contagious, seroprevalence is only 5-15%, so is mask wearing, social distancing, and tiered lockdown the reason for reduction in the spread, or is it partial pre-existing immunity? Evidence from the placebo controlled vaccine studies may help explain more.
There may be some pre-existing immunity. The problem is – how do we test for it? How common is it? Can we predict in any way who has immunity?
A recently published nationwide seroprevalence study from Spain (https://www.bmj.com/content/bmj/371/bmj.m4509.full.pdf) shows 4.5% of the population have a COVID antibody response, suggesting infection or contact with the SARS-CoV-2 virus. The infection fatality rate was 0.8% overall, less than 1 in 10,000 in people under 30, and 8-16% in men over 80. One part of the discussion was whether the low infection rate overall (4.5%) is because a lot of people have existing immunity – if they have pre-existing t-cells and antibodies that fight off COVID. If they do, it doesn’t explain why they don’t make some COVID specific antibodies when they’re fighting of the exposure. The most widely proposed pre-existing antibody to protect against SARS-CoV-2 is other coronaviruses, such as CoV HK01, or HCoV OC43. Against that is the evidence that health care workers, and teachers have higher rates of infection that the general public – if anyone is going to have coronavirus “common cold” antibodies, it’s people who work in a respiratory ward in a hospital, or a school.
I honestly don’t have the answer here, but my take on this is: given the choice of relying on having some pre-existing immunity that hasn’t yet been fully elucidated, so there’s no test we can do to prove whether anyone has immunity or not; or getting a vaccine for which there is a large, and building, evidence base that it will provide a significant immune response and protect against future infection; I would take the vaccine every time.
Should you get the vaccine if you’ve already had COVID?
The clinical studies did not include people who had already had COVID, so I cannot say what the effect will be. When we give the pneumococcal vaccine to people who have had pneumococcus before, the vaccine works in the same way. Every time you get the tetanus vaccine, whether you have tetanus antibodies or not, it works the same way, and you don’t get sick. So my gut feeling is that it will be the same for these vaccines, but there guidance on this will come.
Ultimately, every single one of us wants to get back to some form of normality, as soon as possible. A rapid, widespread vaccination program is a really important part of that process. If are offered a flu vaccine, please consider having that too.
Stay safe. Stick with it. Get the vaccine.