COVID-19 Information Update #2
by Mackenzie Gignac
21 April 2020
A lot has happened in two weeks. We would like to update you on the latest developments regarding the COVID-19 pandemic.
Case Numbers in Australia are Falling
In an unexpected and pleasant development, the growth rates in case numbers in Australia are falling, proving that social distancing is effective. There are very few countries in the world that managed to achieve this. With the “flattening of the curve”, the peak infection is now expected to occur in September, and hopefully, the case numbers at that time will be within our capacity to provide intensive care and ventilation to all patients who require such care. A major reason for the catastrophic death numbers coming out of Italy and Spain is because the number of patients who required ventilation far outstripped their hospitals’ ability to provide it, thus leading to the death of thousands of patients who would otherwise be saved had the hospitals not been overwhelmed.
The Problem is that the Endgame is a Long Way Away
The current restrictions are working well, but case numbers will skyrocket if they are relaxed. Therefore, we are likely to be facing many months of restrictions and general “lockdown” until one of the following occurs:
1. A vaccine is developed.
There is a massive effort to develop the COVID-19 vaccine but even the most optimistic timelines do not expect the arrival of an effective vaccine for at least 12 months. The old tuberculosis vaccine (BCG) has been resurrected from the archives and is currently being tested on health workers to see if it may boost non-specific immunity to COVID-19; even if successful, BCG vaccination will not be the solution for the majority of the general population.
2. Herd immunity is developed.
That is, a sufficient number of the healthy Australian population is infected and develops immunity to COVID-19. Once approximately 50 – 80% of the healthy population has been infected with COVID-19 and became immune to the virus, the virus will likely die out as it runs out of susceptible patients to infect. Based on current projections, this will not occur until mid 2021.
3. We get lucky and the case numbers get low enough that the virus extinguishes itself in the community.
This is a very unlikely scenario. However, if it happens, and we manage to keep our borders closed until the vaccine arrives, we can potentially get back to near-normal life in about 3 to 6 months. Once again, this is a very unlikely scenario, and will almost certainly require further tightening of current restrictions.
What About Anti-Viral Drugs?
There is no drug that is proven to be effective in patients with COVID-19 infection. Many drugs show promising activity in the laboratory, but very few of these will be expected to actually work in humans.
The first attempt at anti-viral therapy came out of China, testing Lopinavir-Ritonavir vs no antiviral therapy in patients with COVID-19 infection (the LOTUS study). Lopinavir is a drug used in the treatment of HIV that showed promising activity in the laboratory against SARS, MERS and COVID-19. Unfortunately, this well conducted study showed that Lopinavir did not work at all in humans with COVID-19 infection, with no improvement in the virus count or the chances of surviving the infection.
2. Hydroxychloroquine (Plaquenil)
The second “anti-viral” drug is one that has been highly advertised by Donald Trump – the old anti-malarial drug Hydroxychloroquine. Some of you may be taking this drug already as it is commonly used to treat joint and skin conditions; you may also find it hard to get this drug at the pharmacy as many people have taken Donald Trump’s advice and stockpiled Hydroxychloroquine, leading to a global shortage. So does Hydroxychloroquine work?
Well, firstly, it is not directly toxic to the virus. Rather, it may modify normal cells in the human body so that it becomes more difficult for viruses to attach to and grow within our bodies. Experiments conducted in animals with other viruses have been failures, variously showing either improvement or worsening of infection with Hydroxychloroquine or chloroquine therapy. Specific to COVID-19 infections in humans, the data is very poor quality, and all we know thus far is that the drug is most definitely not a game-changer.
The hottest drug on the scene at the moment is Remdesivir, an experimental anti-viral drug made by Gilead Sciences that blocks a class of enzymes (called viral RNA polymerases) within viruses like Ebola, SARS, MERS and COVID-19. On April 10th, the New England Journal of Medicine published a report on 61 patients with moderate or severe COVID-19 infection who were given Remdesivir on a compassionate basis (i.e. in desperation and outside of a properly conducted and controlled clinical trial). This was given as a daily infusion through the veins for 10 days.
The group of most interest in this report was the 34 patients who were so sick, they were on ventilators when Remdesivir was started. Of these critically unwell patients, 56% got better, 26% remained the same, and 18% died despite experimental anti-viral treatment. Is this a good outcome? The chance of death for these types of patients in reports from China and other countries range widely between 17% to 78%. So one can argue that the death rate seen so far in patients receiving Remdesivir is at the lower end of expected, at 18%. However, this rate will definitely rise if one remembers that many of the patients who remain alive, but without improvement, will likely die eventually. In conclusion, Remdesivir is not a game-changer, and either does not work, or improves the chances of surviving COVID-19 marginally at best.
Caution is Still the Key
Prevention is still the best way to approach the current COVID-19 crisis.
Remember, probably at least half of young people infected with COVID-19 have minimal or no symptoms, so be cautious with anyone you meet, and take universal precautions.
Stay safe, everybody.
Professor Con Tam, Associate Professor Ali Bazargan, Associate Professor Hang Quach, Dr ShuhYing Tan, Dr Matthew Ku and all the staff from Melbourne Blood Specialists.