Will the vaccine make things worse?

[Bobby]

We are meddling with this Covid disease.
The vaccines could make things much worse
as a new variant could develop that will become
stronger and more deadly if everyone has had the vaccine.

https://www.pnas.org/content/117/15/8218


News Feature: Avoiding pitfalls in the pursuit of a COVID-19 vaccine

Lynne Peeples

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PNAS April 14, 2020 117 (15) 8218-8221; first published March 30, 2020; https://doi.org/10.1073/pnas.2005456117


As they race to devise a vaccine, researchers are trying to ensure that their candidates don’t spur a counterproductive, even dangerous, immune system reaction known as immune enhancement.

The teams of researchers scrambling to develop a coronavirus disease 2019 (COVID-19) vaccine clearly face some big challenges, both scientific and logistical. One of the most pressing: understanding how the immune system interacts not only with the pathogen but with the vaccine itself—crucial insights when attempting to develop a safe and effective vaccine.

But as researchers have discovered, if that person is later infected by a different dengue serotype, then they can develop a severe and potentially deadly illness. In fact, according to one study in the 1980s, more severe responses were found to be 15 to 80 times more likely in secondary dengue infections than in primary infections (4). Instead of the antibodies neutralizing encountered dengue viral proteins, they enhance uptake of the virus. The back end of the antibody binds to macrophages, a type of white blood cell, and helps the virus enter those cells and accelerate viral replication.