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Contrarian view on #vaccines for #Covid-19.

I argue that vaccines might not be the best answer for managing this pandemic. I'm putting my money on anti-virals and other treatment protocols. Hear me out as I make my case and decide if it makes sense. 1/n
2/n Vaccines are tough business. From all the decades of collective knowledge in vaccine development we have, it is very rare that we will get a successful vaccine for any disease. Vaccine development takes years and for good reason.
3/n It's not enough to have a working vaccine, it's efficacy and long term protection it offers is as important. Influenza vaccine has 50-60% efficacy and it is a moving target as the virus mutate every year. Single strand RNA coronaviruses are known to mutate a lot.
4/n Even if we have a working vaccine ready in record time and the virus doesn't mutate as much like the single strand measles virus, long term protection against C-19 is still suspect. BTW the current record for fastest vaccine development is Mumps which is about 4 years.
5/n Given that antibodies in those infected are reducing after 2-3 months and reports of re-infection in a few patients 3-4 months after the initial infection we have every reason to doubt the long term sterile immunity like smallpox.
medscape.com/viewarticle/93…
6/n As per computer simulation models, the vaccine needs to be very effective and at least 70-80% of the global population needs to be vaccinated. This is assuming at least a 80% effective vaccine.
7/n Tall ask for a world which has not managed universal immunisation for infants let alone adults at this scale. Challenges to adult immunisation and equitable immunisation at low cost is immense.I wonder how we are going to vaccinate 7 Billion humans

theconversation.com/how-effective-…
8/n Vaccine effectiveness can vary between regions and have unintended adverse effects. Like the oral polio vaccine was less effective in Indian and African populations making eradication difficult in these regions. RSV and HPV vaccines had adverse events in Indian populations.
9/n There are population demographics that we cannot give vaccines or is counter productive to. Also widespread malnutrition in developing countries make that population poor candidates for vaccinations in general.
10/n We've had scientists working on Malaria, Dengue, AIDS, TB etc. for decades without an effective vaccine we've been lucky in some of course. Small pox, Polio, Measles, Mumps, Rubella, Tetanus, Rabies, Hepatitis A & B, Chicken Pox, Influenza, etc.
11/n There are 150+ vaccine candidates but if your read and hear the experts vaccine development, they all say that there is still a chance that none of them may succeed. But success in vaccines are thought to be a moon-shot. Mumps vaccine took 4 years but most take decades.
12/n It's very rare for a virus to disappear and it is very difficult to achieve it. Smallpox is a big achievement. Polio is close. But we've hardly eradicated more than these 2 viruses. People are still getting infected by the 2003 SARS, 2009 H1N1 (Swine Flu), 2014 Ebola virus.
13/n Even the Chicken pox virus also doesn't leave your body once you get it in childhood. It stays in your body's nerves and causes another severe type of infection called shingles when your body's immunity is down-many decades later.
14/n Even with vaccinations we've not eradicated the humble chicken pox virus Varicella Zoster.
15/n Dengue was thought to be a one time infection like chicken pox but now it is well known that there are 4 distinct serotypes with different virulence. So theoretically one can have dengue 4 times with increasing severity-that is if one survives the first 3 episodes.
16/n
The efforts for a dengue vaccine has been in long in the works. There is a commercially available vaccine since last year but we aren't sure how good a vaccine it is. There are many candidates and whether any of it will work--we are still to see.

pubmed.ncbi.nlm.nih.gov/32024238/
17/n Measles we are seeing a resurgence in many countries now maybe due to the relentless antivaxxers and waning vaccination efforts. The vaccine has more than 90% efficacy and yet worldwide 140,000 children died of it in 2018.

statnews.com/2019/03/26/mea…
18/n HIV is a virus that has been worked on like no other virus-nearly 40 years. Maybe soon overtaken by covid. We still don't have a total cure nor a vaccine. Science w latest drugs have made a straight death sentence into a chronic disease. That is progress but not a cure.
19/n For a disease which has a high percentage of asymptomatic/mild symptoms subjects, about 15 % needing hospitalisation and 2 % fatality, will a vaccine for everybody be better than drugs and treatment protocols which will bring down mortality in the severe cases?
20/n Of course it depends on whether we will be able to come up with better treatments before a working vaccine but from a public health economics perspective, vaccination for such a disease at this scale is not something one can conjure easily.
21/21 To end, I would say that it is good that we've found two early front-runners in the race for vaccines. I'm rooting for it too. The point of this thread is that we should moderate our expectation and pursue other ways to mitigate the pandemic.
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