York uses the Pfizer/BioNTech BNT162b2 vaccine, which is an mRNA vaccine that encodes the spike (S) protein of SARS-CoV-2 — the protein primarily used for viral entry via the angiotensin-converting enzyme 2 (ACE2) receptor expressed on various cell membranes, though specifically relevant in the respiratory tract in this case. The mRNA in the vaccine is delivered to the cytoplasm of our cells via a solid lipid nanoparticle where the host ribosome is used to translate it into the final glycoprotein. This is then processed, transported (bound to the major histocompatibility complex (MHC)) to and presented on the cell surface so the immune system can recognise it. The mRNA is quickly degraded as part of normal eukaryotic mRNA turnover.
The second dose, in addition to triggering the innate immune system, primarily works to reinforce the impact of the adaptive immune system including via memory B cells, memory T cells and immunoglobulin G (IgG) antibodies. This results in longer-term immunity, though it can take 2 weeks for this to build up to full levels in the body. We do not yet know how long immunity lasts following the second dose, but ongoing studies and data from phase-IV trials shall inform us in due course. Although the rate of mutation of SARS-CoV-2 tends to be lower than with influenza, we are likely going to need annual or bi-annual updates to the vaccines to account for antigenic drift — especially as many places in the world don’t seem to be aiming for (or are otherise unable to achieve) eradication.
Here are some pictures from the event (it was a lovely sunny day):
I also shared the news on Twitter, again:
I had a fairly sore arm afterwards, with general myalgia (muscle aches), cephalgia (headache) and nausea on the first night which has now eased off significantly. There have been no other side effects.
I continue to be very impressed with the organisation, information and reassurance provided at these sessions. The NHS and supporting organisations are doing a fantastic job delivering on what is a huge logistical challenge. I feel privileged to be a part of this huge public health campaign for the greater good, however, I also feel disheartened that many of the poorer nations have received a disproportionately lower vaccination rate to date. We need to do more to encourage vaccine equity through initiatives such as COVAX, as while SARS-CoV-2 still exists in the world it presents a risk to all of us.
The reports of blood clotting events with all vaccines (though some receiving worse press than others) have also been a cause of concern for me. Not because I am worried about the safety of the vaccines, but that the events are much lower than the incidence expected in the general population, even for the more rare conditions such as prothrombotic immune thrombocytopenia, and yet are being reported as “vaccine-induced” by some people. There is no evidence that this is the case to date, and I fully expect that causation won’t be confirmed. In virtually all circumstances (unless you have little to no chance of becoming infected), the risk of harm from COVID-19 far outweighs the risk of harm from the vaccine. Many people don’t seem to understand that we are exposed to vastly greater risks of clotting events as part of activities we undertake on a day to day basis (e.g. the use of a wide variety of medications, a sedentary lifestyle or travelling via aeroplane). We all must ensure we protect our wider communities and therefore I would encourage all eligible individuals to get vaccinated at their first opportunity. The more people who are vaccinated, the less likely we are to suffer ongoing clusters of infection due to the rise of new variants.
As with before, I shall continue to abide by the necessary public health interventions as the vaccine programme continues to roll out over the coming months. Although the evidence shows that, in addition to reducing the incidence of severe illness and death, people do seem to have lower viral loads and are therefore potentially less likely to infect others, we must continue in our efforts to avoid increasing transmission of the virus and contributing to antigenic drift. Most data shows a strong neutralising antibody response in the lower respiratory tract (hence greater protection from severe illness and death), but less so in the upper respiratory tract, meaning there is a small risk that people can still transmit the virus.
Moving forward I also intend to continue using face coverings in addition to other relevant basic hygiene measures whenever I am ill with an infectious disease, such as the common cold. I feel this is the respectful thing to do for my fellow humans.
I’m looking forward to my next vaccine, whenever that may be (likely my influenza vaccine in the autumn)!