The current events have ‘forced’ me to do a quick, random analysis of global Covid Vaccination (may not be perfect). A short thread….👇 1/
1-Covid vaccines are not providing good protection against infection including ‘symptomatic disease’: the primary endpoint of their efficacy trials
2-They failed to provide reasonable durability of immune response, more so ag the last two global VOC. 2/
2-They failed to provide reasonable durability of immune response, more so ag the last two global VOC. 2/
3-Though high NAb titers are no guarantee for protection against infection, for a highly immune evading variant like Omicron, one needs several folds(>30-40 folds) higher titers than other variants for protection
4-Frequent boosting is not a sound public health policy. Current vaccines are developed on backbone of the spike that doesn’t match with the Omicron’s spike!
5-Nevertheless, 2 doses of vaccines based on the spike of D614G are providing good protection against severe disease.
5-Nevertheless, 2 doses of vaccines based on the spike of D614G are providing good protection against severe disease.
6-The key public health role of vaccines is prevention of disease what other vaccines like measles, rubella, HepA & B, etc have done/are doing.
7-Prevention of hospitalisation & deaths is the least ambitious goal of vaccines!! Vaccines have eliminated few VPDs like smallpox, polio, measles, etc. And this was not the *primary* objective of the early Covid19 vaccine trials.
9-For prevention of deaths, we have other tools like the antivirals & other therapeutics.
10-But Coronaviruses’ case is different. We could never succeed in developing an effective vaccine against any old CoV: HCCCoVs, SARS, or MERS…..
10-But Coronaviruses’ case is different. We could never succeed in developing an effective vaccine against any old CoV: HCCCoVs, SARS, or MERS…..
11-So, developing >15 licensed products within a span of 15 months was a feat that must be celebrated!!
12-So, where do we go from here? We are still not at the driving seat. The virus is still ahead of us, dictating the terms, and still evolving. The main target of the 🦠 is still to achieve higher transmissibility through immune evasion (selection pressure)
13-On the vaccines front, we need to urgently revise our formulations. All the three aspects need to be bolstered: innate immunity (BCG like ag for trained immunity), mucosal immunity (need intranasal vax), and more effective & specific humoral responses.
14-To achieve the last, we need to have a ‘variant-specific’ or ‘multiple-epitopic/antigen’ vaccines. A ‘spike-only’ approach has probably not worked. Need to exploit more conserved epitopes located at other parts of the virus.
15-Vaccine developers must keep their promise: “will be able to tweak the vaccine shots matching a new variant within weeks”. Let’s commercial ‘considerations’ take a back seat to the scientific needs!
16-So, what do we do? Should focus on ‘VaccinePlus’ approach till the pandemic dies it’s own. After all, in all the past pandemics either vaccines were not available or played only a bystander role!
17-Ultimately, a universal, pan-sarbecovirus vaccine will be required.
But, what about the viability of all these new products? For how long will they be needed? In the post-pandemic era too? Yes, may be. Till the *intimate* human-animal interaction comes to a halt
But, what about the viability of all these new products? For how long will they be needed? In the post-pandemic era too? Yes, may be. Till the *intimate* human-animal interaction comes to a halt
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