“We all hope for a rapid end to the pandemic and an effective vaccine would be a surefire solution. But there are risks that come with a fast-tracked vaccine … “
By William A. Haseltine
Scientific American – The excitement and enthusiasm for a COVID-19 vaccine by the end of 2020 is both palpable and understandable.
We all hope for a rapid end to the pandemic and an effective vaccine would be a surefire solution.
But there are risks that come with a fast-tracked vaccine delivered end of this year, not the least of which are the risks related to the safety of the vaccine itself.
Telescoping testing timelines and approvals may expose all of us to unnecessary dangers related to the vaccine.
While preclinical trials to evaluate the potential safety and efficacy of vaccine candidates are likely to include tens of thousands of patients, it is still unclear whether that number will be large enough and a trial will last long enough to evaluate safety for a drug that would be administered to so many.
The US alone plans to vaccinate hundreds of millions of people with the first successful candidate. One serious adverse event per thousand of a vaccine given to 100 million people means harm to 100,000 otherwise healthy people.
Aside from questions of safety that attend any vaccine, there are good reasons to be especially cautious for COVID-19. Some vaccines worsen the consequences of infection rather than protect, a phenomenon called antibody-dependent enhancement (ADE).
ADE has been observed in previous attempts to develop coronavirus vaccines.
To add to the concern, antibodies typical of ADE are present in the blood of some COVID-19 patients. Such concerns are real. As recently as 2016, Dengavxia, intended to protect children from the dengue virus, increased hospitalizations for children who received the vaccine.
Questions also arise around the efficacy of a potential vaccine. The little we know of the current generation of COVID-19 vaccines raises serious questions regarding their ability to protect people from infection.
We know all the candidates tested to date in non-human primates failed to protect any of the monkeys from infection of the nasal passages, the primary route of human infection … Read more.
William Haseltine, Ph.D., is a former Harvard Medical School professor and founder of the university’s cancer and HIV/AIDS research departments. He also serves as chair and president of the global health think tank, ACCESS Health International. He is author of the upcoming book A Family Guide to COVID-19: Questions and Answers for Parents, Grandparents and Children.
