Chile only doing one dose of SinoVac, interesting video:https://www.youtube.com/watch?v=aGXHpkxtZvo
My opinion is SinoVac definitely needs two doses to really slow transmission.
As it's known that, some vaccines like AstraZeneca and other non-mRNA vaccines, have lower effectiveness in suppressing the virus transmission, while still effective at preventing hospitalization and mild and severe symptom.
In other words, the percentage of asymptomatic carrier of the virus would increase.
Wouldn't it result in the virus spreading around more easily as it's less likely for asymptomatic carriers to be tested and quarantined, thus more chance for them to spread the virus?
Carriers should still have lower viral loads and a shorter time frame they transmit. So I hypothesize the transmission should be reduced.
AZ cuts transmission by 2/3rds after just one dose:https://www.timesofisrael.com/astrazene ... ose-study/
J&J reduces asymptomatic transmission 74%:https://www.webmd.com/vaccines/covid-19 ... s-fda-says
My opinion is that the Western vaccines all reduce asymptomatic transmission.
AZ in the UK looks to be amazing, but how much is lockdown. e.g., France vs. the EU in general is very close in vaccination (and I assume which vaccines), but the behavior (lack of lockdowns, schooling, perhaps weather) of a few weeks ago spiked cases.
However, both the UK and Chile did the one dose strategy. Chile's has not been as successful. I've noticed the reduction in transmissions is close enough to the rated efficacy. So a 2 dose SinoVac has just over 50% efficacy , which means the one dose is some discount. Considering the UAE is trying 3 dose with the different Sinopharm to establish enough immunity, I am of the opinion Chile hasn't been able to fully tame the virus as the transmission is still too high (probably asymptomatic, I'm going to assume most people will try not to get other people sick). https://fintechzoom.com/fintech_news_si ... 20data.%29https://ourworldindata.org/explorers/co ... +Union~CHLhttps://ourworldindata.org/explorers/co ... pean+Unionhttps://www.msn.com/en-ae/news/national ... uxbndlbing
So I think asymptomatic transmission will decrease as the likelihood should decrease, I hypothesize about the efficacy rate less, and the duration should be reduced. However, if behavior is more towards transmission (less lockdown), then it will increase transmission. This is why it takes a very high fraction of society vaccinated to matter.
Herd immunity will not mean no transmission. It will not mean no deaths either. It just means the risk is low enough to allow "normal" life to resume. Each person (including children) will need to be vaccinated to protect themselves. It will be the side benefit that they are less likely to transmit the disease.
We've discussed many times in this thread how viral load and that will reduce transmission. https://www.jpost.com/health-science/co ... udy-664181
So all evidence is the opposite of yoru theory. Vaccines will reduce transmission for a given behavior. Since people will misbehave, it is necessary to get vaccine to all.
The mRNA vaccines are just 90%+ efficacy. That drop an Ro of 4 down to 0.4 or much less (disease burns out quickly, see Israel or UK which is also doing lockdown). The low efficacy SinoVac will only drop that down to a theoretical Ro of 2. Errr... that means to get Ro < 1, with SinoVac, everyone must be vaccinated or have natural immunity.
While Israel, with 90% efficacy slowed the virus to a non-event iwith 60% vaccinated (plus natural immunity) and the UK has done really well with 45% vaccinated (plus high natural immunity and lockdown), the lower efficacy will have issues.
But what is the solution? With have just over 700 million doses administered for a mere 399 million people into a population of 7.9 billion or so. https://ourworldindata.org/covid-vaccinationshttps://ourworldindata.org/grapher/peop ... ID_WRL~CHL
The most optimistic analysis, in my opinion, is that we might get 2 billion people inoculated with mRNA in 2021. The other vaccines will hopefully get a few billion more people. We're really only on track to vaccinate half the people in 2021. So to slow the virus, we need to use every effective vaccine *unless* a factory can be converted to make something better.
But as the recent J&J debacle has shown, vaccine production is hard. My opinion is there is normally years to debug manufacturing and our trying to do it quickly led to the 77 million doses suspect (OK, 15 million must be destroyed, 62 million suspect): https://news.yahoo.com/62-million-doses ... 32534.html
The next wave is here. At this point only a lucky few can be picky on vaccine (I'll fully admit to being a lucky person). Most countries and thus most people would be just happy to have much more supply to have that chance to stay out of the hospital. Happy to have a reduced chance to transmit it to a child (even better, vaccinate the children, but that is something for the summer for the lucky early countries).
I'm happy my neighbor received J&J. I'll take a 74% reduced chance of infecting my kids over him having to wait weeks for better.
With a majority of vaccine not being mRNA in the UK, they have tamed the virus. Not perfectly (e.g., spread among the younger unvaccinated), but a good start. https://www.worldometers.info/coronavirus/country/uk/
5 months without TV. The best decision of my life.