429 CMAAO CORONA FACTS and MYTH 26th Post Vaccine Breakthrough COVID
Dr K K Aggarwal
429 CMAAO CORONA FACTS and MYTH 26th Post Vaccine Breakthrough COVID
Dr K Aggarwal President CMAAO, HCFI
With input from Dr Monica Vasudev
What can be the reasons in India
1. Over use of antibiotics and anti-virals leading to NSP 14 inhibition and new strains of the viruses leading to breakthrough cases.
2. Breakthrough infections means that the virus has been able to break through the defences created by the vaccine.
3. Breakthrough infections' are expected in a small number of people after vaccination
4. Some may have been infected before the jab but some strains may evade vaccine protection. These strains ( newer strains in India) may aggravate or facilitate covid. (also, Israel observation)
5. In India also we are clinically seeing a lot of early breakthrough cases
Evidence for increased breakthrough rates of SARS-CoV-2 variants of concern in BNT162b2 mRNA vaccinated individuals
Talia Kustin, Noam Harel, Uriah Finkel, Shay Perchik, Sheri Harari, Maayan Tahor, Itamar Caspi, Rachel Levy, Michael Leschinsky, Shifra Ken Dror, Galit Bergerzon, Hala Gadban, Faten Gadban, Eti Eliassian, Orit Shimron, Loulou Saleh, Haim Ben-Zvi, Doron Amichay, Anat Ben-Dor, Dana Sagas, Merav Strauss, Yonat Shemer Avni, Amit Huppert, Eldad Kepten, Ran D. Balicer, Doron Nezer, Shay Ben-Shachar, Adi Stern
doi: https://doi.org/10.1101/2021.04.06.21254882
The SARS-CoV-2 pandemic has been raging for over a year, creating global detrimental impact. The BNT162b2 mRNA vaccine has demonstrated high protection levels, yet apprehension exists that several variants of concerns (VOCs) can surmount the immune defenses generated by the vaccines. Neutralization assays have revealed some reduction in neutralization of VOCs B.1.1.7 and B.1.351, but the relevance of these assays in real life remains unclear. Here, we performed a case-control study that examined whether BNT162b2 vaccinees with documented SARS-CoV-2 infection were more likely to become infected with B.1.1.7 or B.1.351 compared with unvaccinated individuals. Vaccinees infected at least a week after the second dose were disproportionally infected with B.1.351 (odds ratio of 8:1). Those infected between two weeks after the first dose and one week after the second dose, were disproportionally infected by B.1.1.7 (odds ratio of 26:10), suggesting reduced vaccine effectiveness against both VOCs under different dosage/timing conditions. Nevertheless, the B.1.351 incidence in Israel to-date remains low and vaccine effectiveness remains high against B.1.1.7, among those fully vaccinated. These results overall suggest that vaccine breakthrough infection is more frequent with both VOCs, yet a combination of mass-vaccination with two doses coupled with non-pharmaceutical interventions control and contain their spread.
1. The BNT162b2 mRNA vaccine has demonstrated high protection levels, yet apprehension exists that several variants of concerns (VOCs) can surmount the immune defenses generated by the vaccines.
2. Neutralization assays have revealed some reduction in neutralization of VOCs B.1.1.7 and B.1.351, but the relevance of these assays in real life remains unclear.
3. The above study performed a case-control study that examined whether BNT162b2 vaccinees with documented SARS-CoV-2 infection were more likely to become infected with B.1.1.7 or B.1.351 compared with unvaccinated individuals.
4. Vaccinees infected at least a week after the second dose were disproportionally infected with B.1.351 (odds ratio of 8:1).
5. Those infected between two weeks after the first dose and one week after the second dose, were disproportionally infected by B.1.1.7 (odds ratio of 26:10), suggesting reduced vaccine effectiveness against both VOCs under different dosage/timing conditions.
Discussion
1. Our results show that there is an increased incidence of VOC B.1.351 in vaccine breakthrough infections in fully vaccinated individuals with BNT162b2, and increased incidence of VOC B.1.1.7 in partially vaccinated individuals
2. These results are generally aligned with those from in vitro neutralization assays that have shown a large reduction in neutralization against B.1.351, and little to no reduction against B.1.1.7 in fully vaccinated individuals
3. Suggests that serum-based neutralization studies that take into account individual monoclonal antibody responses may provide a good proxy for real life protection in the case of SARS-CoV-2
4. Sequencing limitations prevented us from sequencing very low viral load samples (Methods), and thus the focus of our study was on vaccinees who generated higher viral loads.
5. However, it has been shown that cases with low viral load may be a lesser concern from a public health perspective, as they are associated with less symptoms and decreased transmission
6. Finally, our FE cohort is based on infections documented seven or more days post the second vaccine dose
7. Some subjects in this cohort may have been infected before the immunity from the boost was fully established, and it is thus possible that enhanced immunity from the boost, which develops over time may more effectively prevent infection with the B.1.351 variant.
8. Our current study may suggest a somewhat lower protection B.1.1.7 in the first weeks after the first vaccine dose.
9. From a biological point of view, the breakthrough cases observed in this study might either be due to immune evasion of both strains, or the ability of B.1.17 to create higher viral loads