Ways in which things could get better or worse
Vaccine
The media have reported experts’ estimates that a vaccine could be available in 12-18 months. However, these estimates are guesswork. It took five years to create a vaccine for Ebola, and that was a record. Technology has improved since then and a trial vaccine has already been injected into human subjects [20], but these new technologies have not been used to defeat a new virus before. It is also a problem that vaccines can be dangerous – an effect called “immune enhancement” can actually help a virus to infect cells – which means that proper testing is essential [19, 21]. And as the Imperial College scientists observe, there is no guarantee that early vaccines will have high efficacy [2]. This explains why it is unlikely that vaccination is a core part of the government’s plan. However, it will clearly be helpful if a vaccine can be found.
Treatments
A variety of drugs and treatments are being developed or tested against COVID-19, including existing antiviral medicines, blood plasma from people who have had the virus, arthritis drugs, artificial antibodies (potentially early autumn) and new antivirals (2021 at the earliest) [21]. The World Health Organisation has launched a trial of the most promising existing drugs, which are: “[i] an experimental antiviral compound called remdesivir; [ii] the malaria medications chloroquine and hydroxychloroquine; [iii] a combination of two HIV drugs, lopinavir and ritonavir; and [iv] that same combination plus interferon-beta, an immune system messenger that can help cripple viruses.” [22]
We should bear in mind that clinical trials often fail and promising drugs often turn out to be useless or even harmful. It is therefore difficult to predict when a reliable treatment could be available. But a serious and coordinated global effort is under way.
Population immunity
Some disease models have suggested that more people could have the virus than was initially thought. A paper from scientists at Oxford [23] shows that 36-68% of the UK population could be infected, while another paper argues that cases in Italy could be 15 times reported numbers [24]. We may hope that is true, but at the moment these are just models [25].
To discover the reality, what is required is widespread testing not just for active infections, which is what is mostly happening at the moment, but for antibodies to the virus in people’s blood [26]. That will tell us not only who has the virus, but who has had it (and could therefore be immune). Antibody testing is already being rolled out: the UK has ordered 3.5 million tests in the first instance and is planning to begin home testing.
It may turn out that fewer people have already been infected than we might have hoped, but antibody testing will also be useful in the exercise of keeping outbreaks under control once lockdown is lifted, and may be helpful in getting people back to work.
Seasonality
COVID-19 may become less of a threat in the summer (it appears to be more prevalent in the northern hemisphere at present, but that could be reporting bias). On the other hand, even if it does, action to contain outbreaks could become a seasonal necessity, recurring every year [27]. According to one new modelling paper [28], this is likely if immunity to the virus is not permanent – in other words, if you can re-catch it after a few months, as with some cold viruses. If immunity is permanent, the virus could disappear in five or more years after causing a major outbreak.
Fatality rate
As has happened in previous pandemics, the number of infected people who die of COVID-19 is probably inflated because of the lack of testing of people who are not badly ill. Unfortunately, at this point in time we cannot know what the true fatality rate is [29].