A Covid-19 exit strategy for NepalNepali Times medical columnist assesses ongoing research into diagnosis, therapy and vaccines
The Nepal Health Research Council has decided to allow international researchers to conduct Covid-19 vaccine trials in the country as part of a global effort to stop the virus. However, this is not a panacea, and an exit strategy from this pandemic should not just include vaccines.
Vaccines may or may not work, and their immunity rates will vary. Other methods for tackling SARS-CoV-2 need to include diagnostics and therapeutics.
At present the definitive diagnosis is made by a cumbersome and sophisticated RT- PCR (Reverse Transcription Polymerase Chain Reaction) with a sample taken from the back of the mouth or naso-pharynx.
More user-friendly tests need to be made available soon if we are to make testing easier and more prevalent. Scientists are trying to see if saliva samples can replace the awkward oral or nasopharyngeal swab samples.
Ideal would be a RDT (Rapid Diagnostic Test) like a dip stick test, similar to what is available for pregnancy that does not require well-trained technicians and can be performed at home. This is easier said than done, but scientists are feverishly (pun intended) working on trying to make a much simpler test than PCRs available now.
If a diagnosis using RDT is promptly and accurately made available in large quantities, it will be easier to decide who to isolate, and hence inhibit transmission of the virus – the main tenet of Covid-19 control.
In addition, the importance of prompt testing is underlined by the fact that as the Nepali winter approaches there will be influenza and other viruses which may be mixed up with SARS-CoV-2, leading to unending confusion about who to isolate if tests are not easily available.
In Nepal we know all to well the consequences of a wrong diagnosis, using RDTs such as the Widal Test to diagnose typhoid fever. Post-2015 earthquake in Nepal, many false-positive Widal Tests lead to treatment for typhoid fever when the patient in reality had typhus fever, a totally different disease which required a different antibiotic. As a result, the typhus fever was not controlled, sometimes with fatal consequences.
Treatments make up the other important exit strategy to rid the world of the pandemic. If a single, effective treatment (none exists so far) is found, it will not only help the index patient but also mitigate transmission of SARS-CoV-2.
In terms of treatment research, randomised controlled trials (RCTs) are much more reliable and superior to observational studies of patient treatment as bias can lead to incorrect conclusions. In addition a large sample size, RCTs may be able to give a definitive answer.
The importance of a proper sample size is illustrated by this example. Chinese doctors in Wuhan did such a good job in controlling Covid-19 that when they performed RCTs on Covid-19 patients using Remdesivir (an expensive antiviral drug, now available in Nepal ) in their hospital, they ran out of patients to study and did not have a large enough sample size to arrive at a definitive conclusion.
Subsequently other groups studied Remdesivir and showed that it cut down the days (not mortality) in hospital for the sick patient. It was a spot of good luck that the largest (9,000 patients) randomised trial in for Covid-19 from the UK (the Recovery Trial) showed that the cheap steroid, Dexamethasone, although not a silver bullet, significantly decreased mortality in patients requiring oxygen.
In the treatment of Covid-19, cost effectiveness will be an even more important factor for countries like Nepal. Ventilators may be important, but they are the last resort. Worldwide up to 90 % of Covid-19 patients on ventilators succumb to their illness because their condition is already so serious when they are attached to the machines.
In this part of the world where a functioning arterial blood gas machine to help with the ventilator settings and other technical issues like availability of adequate oxygen are already potential problems, getting ventilators to work properly may also be an issue.
The Covid-19 pandemic is a saga, it is a marathon not a 100 metre sprint. It will be important to be psychologically ready for the long-haul with this virus until at least one of the strategies -- vaccine, diagnostics or therapeutics -- works well.
Luck is obviously going to play a big part in all of this, including serendipitous findings of which there is a history in medical research. Remember Alexander Fleming’s accidental discovery of penicillin?
The good news is that the best scientific minds in the world are devoting all their time and energy in finding a way out. There is a lot of punditry and advice floating about, but most of it is at best guess work because this is a very wily virus.
The Nepal government has got its work cut out with the surge of the past month, it has to monitor the situation closely with the mantra of test, isolate and treat – as well as listen carefully to scientific facts, not rumours.
Frequent hand washing is probably as important as distancing and wearing a mask, and adequate soap and water has to be provided including in quarantine areas. The government should not pretend the situation is getting better as it did when it lifted the lockdown on 21 July. It is better to be over-prepared than under-prepared with periods of on-and-off lockdowns in the coming months.