In September I wrote a blog about my optimistic take on the coronavirus research at that time. In late summer the UK and most of Europe had experienced a heartening drop in coronavirus cases. In London we were able to meet friends, go out for meals, and enjoy something close to normal life again.
Three months on, I’m writing again as we emerge from our second nationwide lockdown, but with most of the country still under strict restrictions under our 3-tier system. The threat of the second wave of coronavirus during the winter has unfortunately become a reality and many of the predictions in my last blog were perhaps a little too optimistic. But how many of these predictions were correct?
Where are we now with the coronavirus research?
Read on to find out…
Vaccines
Achieving approval of an effective vaccine within 12 months is an incredible feat of biomedical research, made possible by the hard work of multi-national teams of scientists in an historic moment for world public health. However vaccine scepticism in the UK has risen since March, so an NHS campaign to publicise the proven safety of the upcoming coronavirus vaccines is underway.
In the UK there are currently 3 main vaccines in the limelight but there are many other in development. Last week, the coronavirus vaccine developed by Pfizer/BioNTech became the first to be approved for use in the UK. The first dose of this coronavirus vaccine was administered yesterday to 91 year old Margaret Keenan, described by her as “the best early birthday present I could wish for.”
This is an mRNA vaccine which contains the gene for the coronavirus spike protein (see my previous blog for more information on the types of vaccine currently in clinical trials). This means that once this vaccine is injected into our arms, specialised immune cells will then pick up this gene and use it to produce the spike protein. The immune system then learns what this spike protein looks like so that immune cells will recognise it quickly if we are exposed to the spike protein on the surface of the real virus. This speed is key to the immune system eliminating the virus before it has a chance to make you ill.
Results from the final clinical trial reported on the 18th of November said that the Pfizer/BioNTech vaccine is over 90% effective at preventing disease: of 42,000 participants enrolled on the trial, 170 people fell ill with coronavirus. Only 8 of these people were given the real vaccine, 162 were given a placebo (95%).
On the 30th of November, another mRNA vaccine produced by Moderna was reported to have a similar efficacy of 94%, and no one given this vaccine developed severe covid. On the same day, Moderna applied for emergency authorisation for rollout of this vaccine.
The vaccine developed by Oxford University and AstraZeneca was also recently reported to be around 90% effective at preventing coronavirus. Unlike the Pfizer/BioNTech and Moderna candidates, this is a viral vector vaccine which uses a harmless virus to deliver the coronavirus genes to our cells. However, this vaccine has the advantage of being far cheaper and easier to store and transport than the Pfizer/BioNtech vaccine as it can be kept in the fridge instead of needing to be frozen.
Although the Pfizer/BioNTech vaccine was the first the be approved, it is it likely that other vaccines will soon follow. Researchers are still yet to determine how long the immunity given by these vaccines will last.
Hope for longer COVID immunity
One of the first pieces of research into how long coronavirus immunity lasts worryingly reported that coronavirus antibodies decline after a few months. But new research has shown that antibodies and the cells that are specialised in remembering how to tackle the coronavirus are still present in the blood months after infection.
The study monitored 185 people who had recently recovered from coronavirus for a minimum of 6 months. They found that the amount of antibody circulating in the patients’ blood varied wildly from person-to-person, but 90% of participants still had detectable antibodies 6 months after infection. Memory B cells which make the antibodies specific to the coronavirus ‘spike’ protein were more numerous at 6 months post-infection than immediately after recovery. Finally, memory T cells which destroy virally infected cells were still present in 89% of participants after 6 months.
These results still cannot give a definitive answer to how long a person is immune to the coronavirus as this disease simply hasn’t been around long enough. However, this research is consistent with findings that survivors of the original SARS outbreak in 2003 retained SARS antibodies in their blood for up to 3 years after infection. But these people still had detectable SARS-specific memory T cells in their blood 17 years after infection. This is extremely encouraging news for all who hope that long-term immunity to covid might too be possible.
Early in the pandemic, there were concerns that many people were becoming reinfected with the coronavirus shortly after leaving the hospital, but it’s now thought that these cases were mainly down to these people being unable to clear the virus from their systems within the expected timeframe. There have been sporadic reports of true repeated infections in the same individuals, however, these cases seem to be very rare. A better understanding of the length of covid immunity will also help to determine how frequently vulnerable people will need ‘booster’ vaccines.
Have treatments for coronavirus improved?
The sharp increase in the number of cases in the UK since April can be explained by increased testing. But despite the increase in cases, it is estimated that the death rate has been falling since the spring, and this pattern is being observed in other countries.
In interviews featured in a Nature News article, many doctors shed light on why this might be. As covid was a new and daunting disease to the UK in March, this put pressure on healthcare teams to try new drugs which had not yet been proven to reduce coronavirus mortality. These included interventions such as anti-interleukin-6 antibodies, the antiviral drug Remdisivir, and plasma from recovered covid patients, and hydroxychloroquine; all of which have failed to show efficacy so far in clinical trials.
The intensive care wards with the best survival rates cared for their patients using drugs and interventions that have been tried and tested over decades in patients suffering from respiratory infections (e.g., not using ventilators until absolutely necessary).
Early in the pandemic, doctors realised that in severe covid patients their immune cells went into overdrive while attempting to clear the virus and this led to irreversible organ damage. As a result, a number of existing drugs that work by suppressing the immune system were trialled in these patients. The only drug that has been shown to boost the survival of critically ill covid patients is the anti-inflammatory steroid dexamethasone, which is already routinely used in intensive care units to manage some other respiratory infections.
The RECOVERY trial concluded that dexamethasone reduced fatalities by up to one third and should be used to treat severe covid patients. It’s possible that the drop in fatalities may be linked to healthcare workers now being familiar with how to manage the care of covid patients.
Lockdown and Testing Updates
It was hoped that a second lockdown would not be necessary, but the UK government announced another national lockdown during November after the number of new cases began spiralling out of control. It is estimated that coronavirus infections dropped by 30% during this period, and the plan to test students on mass using rapid antigen tests before they return home for Christmas is intended to keep cases manageably low over the festive period.
The government’s plan for a covid ‘amnesty’ over Christmas in which up to 3 households will be allowed to mix has been criticised by scientists as this could ‘throw away gains in suppressing the virus… (when) we’re on the cusp of being able to protect those elderly people who we love through vaccination.’
Preventing the virus from spreading during December is crucial. We now know that the virus is most transmissible in indoor settings with multiple people in close contact, and so large family gatherings give the virus the perfect opportunity to spread.
If we can minimise the number of new coronavirus cases over Christmas, more people will survive into a period where deaths can be prevented through vaccination. We have now reached a critical point where this disease is gradually becoming less fatal due to improvements in treatment and a vaccine is close at hand. With this in mind, we should continue to take precautions over Christmas and look forward to vaccination in 2021 with fresh optimism.
