Sumary of Research on SARS-CoV-2 breakthrough infections shows the danger posed by Delta:
- Scientists from Florida, USA, have conducted a study to determine the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission from individuals with delta breakthrough infections.
- The findings reveal that delta breakthrough cases exhibit a relatively lower viral load compared to unvaccinated cases.
- However, in the majority of delta cases, the viral load is above the transmissibility threshold.
- The study is currently available on the medRxiv* preprint server while awaiting peer review.
- Background With the progression of the coronavirus disease 2019 (COVID-19) pandemic, several novel variants of SARS-CoV-2 with increased fitness have emerged in many countries across the globe.
- The SARS-CoV-2 delta VOC, first identified in India, contains multiple spike mutations that make the virus more infectious and resistant to infection- or vaccination-induced immunity.
- In the US, a sharp rise in new delta cases and related hospitalization has been observed since June 2021, despite a high vaccine coverage.
- This indicates declining vaccine immunity against the delta variant.