Why vaccines, not drugs, are our only possible way out of the pandemic
Theoretically, drug-based protection may be attainable, but the practicalities suggest otherwise
This article is, perhaps surprisingly, not about the evidence around the usefulness of ivermectin to prevent or treat Covid-19.
Up to Monday July 26, there were 75 clinical trials on the use of ivermectin for Covid-19 listed on the US National Library of Medicine’s ClinicalTrials.gov, the authoritative global database for all registered and approved clinical trials. Most are still ongoing and there will undoubtedly be others registered in the near future, so we are probably still a long way off from the last word on that topic. But I came to the realisation that that is not the point. Even if these trials demonstrate fantastic success of ivermectin, or any other drug, in the prevention and/or treatment of Covid-19, such drugs will not provide us with a way out of the pandemic.
When you recover from a viral infection, it marks the end of the road for all the virus molecules you had in your body. Viruses need to infect new hosts all the time to keep going. However, every time a virus meets a dead end, in other words a potential new host that turns out to be immune to infection, its odds of having a future drop considerably. That is the principle behind and the beauty of herd immunity. If everybody, or almost everybody, is immune, the virus has no other option but to go away.
Vaccines provide long-term immune protection against viral infections and have the potential to eradicate these diseases. We know this from our global success at eradicating polio towards the late 1990s and smallpox in the late 1970s. International donors, led by the US, contributed about a third of the costs — $98m (about R1,4bn) — towards smallpox eradication efforts and it was subsequently calculated that the US recouped its contributions every 26 days due to the savings of not having to vaccinate or treat smallpox any more. That number becomes very relevant if you consider how much money we now spend on our collective Covid-19 protection and treatment measures, as well as the enormous economic costs of lockdowns, social restrictions, grants and business relief.
On the other hand, drug-based herd protection against Covid-19 might be achievable in theory, but it would require the constant cooperation of every person on the planet. That is because drugs only work for as long as you take them and to end the pandemic with a drug, you would need every person around the world to take that drug every day. No room for drug hesitancy or issues around side-effects or interactions with other drugs, no free passes for pregnant or breast-feeding women and definitely no room for global supply shortages. And because the drug treatment would probably not involve long-term stimulation of the immune system, total eradication of the virus would be unlikely. In short, we would all be dependent on that drug, forever.
Doctors who treat TB patients will attest to how difficult it is to get them to take their medication consistently for 18 months. And this is for a disease these patients have and presumably want to get cured of. Now imagine the odds that people will keep on consistently taking a drug for decades to come to prevent a disease they don’t have.
Every time somebody drops the ball, we would be back to square one. And if you take issue with the amount of money that vaccine manufacturers are earning from global vaccination programmes, imagine what it would mean for pharmaceutical companies who produce a drug, even a cheap drug, that every person on Earth has to take every day for the rest of their life. Even small amounts of money become quite big if you multiply them by seven billion people, then by 365 days, and then by 20 or 50 years. Talk about the gift that keeps on giving.
Doctors who treat TB patients will attest to how difficult it is to get them to take their medication consistently for 18 months. And this is for a disease these patients have and presumably want to get cured of. Now imagine the odds that people will keep on consistently taking a drug for decades to come to prevent a disease they don’t have. I generally have faith in humanity, but I doubt this is a realistic scenario. Consequently, such a drug programme will always just be an add-on: anti-Covid-19 drugs and masks and social distancing. Still no return to the way things were before.
Regardless of your thoughts on the speed at which Covid-19 vaccines were originally developed and tested, we now have more than nine months of real-world data from many countries that show these vaccines are safe and effective. In the US, 99% of patients who died of Covid-19 over the past few months were unvaccinated. And because the same vaccines are used in SA, the US, UK and Europe, we can be guided by their data. Follow-up tests on the first receivers of the Johnson & Johnson (J&J) and Pfizer vaccines have shown that immunity against Covid-19 lasts for at least nine months. (That is because these people only received their vaccines nine months ago and we have therefore only been able to monitor their immunity for that period.) Towards the end of this year we will know whether vaccine-induced immunity lasts for a year. Towards the end of next year we will know whether it lasts for two years. And so on and so forth.
Research also shows a significantly stronger immune response to Covid-19 vaccines than to natural Covid-19 infection, especially in people who only had mild disease. Even if the follow-up data show we may need booster shots, it will still be something that will need to happen only once every few years, not every day, and it will be far less risky than building immunity through Covid-19 infection. Vaccination programmes can also be monitored closely, so we know how many of our fellow citizens are vaccinated. Drug programmes, on the other hand, cannot be monitored. You can hope your colleague or the person in the queue behind you at the shop took his/her anti-Covid-19 medications that morning, but short of mandatory daily drug tests for everyone, we will have no way of managing and ensuring adherence to a drug-based Covid-19 prevention programme.
Of course, we should keep testing drugs for the treatment of Covid-19. It would be fantastic if we could design a treatment that would successfully treat all infections, and repurposing existing drugs will get us there faster. Therefore, I support high-quality research into ivermectin and any other drug that shows promise in this regard. But a comprehensive global vaccine programme is the only possible chance we have of finally and irreversibly finding our way out of the current pandemic. To be able to travel again. To eat at a restaurant, drink in a bar and dance in a club. To attend in-person conferences, sporting events, music concerts, festivals, religious gatherings, large wedding receptions. And yes, even funerals, where we can laugh and cry and sing and hug, without masks and without worrying who among us will be dead next week.
Dr Hanél Sadie-Van Gijsen is affiliated with the Centre for Cardio-metabolic Research in Africa (Carma) in the Division of Medical Physiology at the Faculty of Medicine and Health Sciences at Stellenbosch University.