Let’s focus on a small communist country of 11 million people #Cuba. Let’s see what Cuba is doing with their multiple vaccines & on Covid front! All the COVID vaccines developed in Cuba are what are known as protein subunit conjugate vaccines. 1/
Cuba now has five vaccines in various stages. Soberana 1, Soberana 2 and Soberna Plus, Abdala and Mambisa.
One is a nasal spray still in clinical trials. 2/
Cuba didn’t want to rely on the whims of foreign governments or international pharmaceutical companies to immunize its people. Cuba didn’t even sign up for the #COVAX program. 3/
None of them have yet been authorized by the #WHO or any other major international regulator.
But they’ve allowed Cuba to boast one of the highest COVID vaccination rates in the world. More than 85% of the island nation is fully immunized against the virus. 4/
It even tops every country in Europe except Portugal. The country is even giving the shots to kid as young as 2 years old.
At a time when many other #LMICs continue to struggle to get enough doses, Cuba is exporting vaccine to Iran, Venezuela, Mexico, Nicaragua and Vietnam. 5/
Their priorities were to focus in working on the vaccine and get the clinical trials done so that people could get immunized. Not to write a paper or get that paper published. 6/
Are their vaccines working?
If you compare recent cases and deaths in Cuba with Israel, Cuba does not seem to have had an Omicron wave of anything like the same magnitude. Lots of possible reasons, but it suggests their vaccines work. 7/
Throughout the pandemic, they’ve done what so many other nations couldn’t — controlled their own fate when it came to getting vaccines. 8/
Just learn few fascinating things regarding the evolution of #SARSCoV2, pathogenicity of common cold coronaviruses (CCC), and the development of a new live attenuated vaccine candidate 1/
Those who think that the #Spike protein of #SARSCoV2 has ‘exhausted’ all its options to surprise us owing to limited space to undertake infinite mutations need to rethink & revise their opinions. 2/
A comparatively old paper on human coronavirus CoV-229E hints that 25 of the 31 receptor-contacting RBD residues in HCoV-229E have varied during virus's evolution in humans over the past 50 yrs. @jbloom_lab 3/
Antibody & Memory B-cell immunity in a heterogeneously #SARS2 infected & vaccinated population from #Mexico where five different vaccines have been deployed to populations with high SARS2 incidence. 1/
Levels of antibodies that bound a stabilized prefusion spike trimer, neutralizing antibody titers & memory B-cell expansion correlated with each other across vaccine platforms. 2/
Neutralizing antibody titers against SARS-CoV-2 variants vary between different vaccines: different vaccines elicited variable levels of B-cell immunity, & the majority of recipients had undetectable neutralizing activity against the recently emergent omicron variant. 3/
NIAID/NIH researchers developed a replicating RNA vaccine expressing the Omicron (B.1.1.529) spike. They conducted animal studies for the following objectives:
1-How does pre-existing immunity affect the antibody response to an omicron-targeted booster vaccine (in mice) 1/
In mice, their main objective was to evaluate the effect of pre-existing immunity on the antibody response to the B.1.1.529-targeted vaccine (using an influenza repRNA vaccine to control for background immunity to the repRNA backbone) 👇 2/
2-In hamsters, the main objective was to evaluate the protective efficacy of a single-dose B.1.1.529 repRNA vaccine relative to the ancestral A.1 repRNA vaccine following infection with B.1.1.529 virus as shown in the study design 👇 3/
In a new study, the researchers develop a panel of mRNA-LNP-based vaccines using the RBD of #Omicron & #Delta, which are dominant in the current wave of COVID-19. 1/
In addition to the Omicron- & Delta-specific vaccines, the panel also includes a “#Hybrid” vaccine that uses the RBD containing all 16 point-mutations shown in Omicron & Delta RBD, as well as a #bivalent vaccine composed of both Omicron and Delta RBD-LNP in half dose. 2/
Interestingly, both Omicron-specific & Hybrid RBD-LNP elicited extremely high titer of NAbs against Omicron itself, but few to none NAbs against other SARS-CoV-2 variants. 3/
A newly dominant variant can reinfect only those who got infected with prior variants, but same-variant reinfection is extremely unlikely. This pattern seems to hold for ancestral variants & Delta 2/
A new @NatureMicrobial report: Despite a marked ⬇️ in NAbs over time, NAb responses persist for up to 480 d in most convalescents of symptomatic COVID19, whereas a high rate of undetectable NAb responses was found in those w/ asymptomatic infections 3/
The rise of #SARS2 variants & evidence of immunological interference (like OAS & weakened T-cell immunity) underscore the need for preemptive, next-gen vaccines that confer broad protection ag Covid
What is common between Denmark, Israel, Austria, France, Switzerland, the UK, and the US? They all suffered an unprecedented severe wave of Omicron despite having some of the highest vaccination rates in the world. 2/ @1amnerd@thewire_in
@1amnerd@thewire_in Most of the Covid19 vaccines are based on spike-protein of SARS2. They have worked reasonably well so far. However, with the advent of #Omicron, one of the most mutated variants has exposed the limitations of these vaccines, particularly their ability to prevent infections 3/