Question: I, like many others, was deeply encouraged and hopeful to learn that the COVID-19 vaccine being developed by Oxford in the UK shows some promise. Not to be a downer, but I feel the need to ask: Especially under an accelerated timeline such as the researchers are working under, how do you test a vaccine to see if there could be any long-term effects down the line? Is there a way to see if a vaccine in 10+ years could lead to increased risks of cancer or other problems, without actually waiting that long? Or are there just some things that we know a vaccine is not capable of doing?
Answer: It’s better to address vaccination concerns early and often, so thanks for asking this question. I’d like to think that we can find the balance with expedited vaccine development and vaccine safety and I know that myriad groups are trying to do just that. Last month, Scientific American published this opinion piece that describes concerns about “telescoping the [vaccine] testing timelines” and back in March, Nature published this viewpoint expressing similar concerns. Meanwhile, vaccine development needs to be expedited to help prevent more infections and save lives in this bleak pandemic we’re suffering through!
How do we monitor vaccine safety?
We talked about the vaccine development cycle in our Q&A of 5/13. Throughout the cycle, scientists are monitoring not only whether the vaccine works to prevent infection, but also whether the vaccine leads to any adverse outcomes. This monitoring spans early phase animal studies, through clinical development and human trials, and for vaccines that make it to widespread use (e.g. those deemed both safe and effective), the monitoring continues for quality control and adverse event reporting in the general population. CDC offers this great history of vaccine concerns, as well as this helpful resource describing common vaccine questions and concerns. In short, the vaccines we currently use are very safe! No vaccine is linked to cancer.
Concerns about COVID-19 vaccine roll-out
In the context of expedited vaccine development for COVID-19, safety remains paramount. And concerns that groups are rushing vaccines to widespread use without enough safety data are valid. For example, Reuters reported last month that “China’s Central Military Commission approved the use of a [CanSino-developed] vaccine by the military on June 25 for a period of one year.” The vaccine is still in human trials, but is being rolled out to China’s military (est. 2 million individuals)! In a similar vein, here in the United States, we had the massive roll-out of a proposed COVID treatment — hydroxychloroquine — before its safety was well understood. As data came in, FDA cautioned against hydroxychloroquine use and revoked its emergency use authorization because the drug was found to cause serious heart problems (big adverse event) and no benefit for hospitalized patients (no effectiveness). Would the US similarly roll-out a vaccine before we had enough safety and effectiveness data? Would other countries?
Considerations for further addressing vaccine safety concerns
In addition to the safety monitoring components of the vaccine development cycle, another avenue to monitor safety that will require increased investment is post-market vaccine safety studies, which StatNews described last week. And still another avenue is data sharing and transparency. Results on vaccine safety should be published in peer-reviewed journals, like this piece published two days ago in Lancet, and should be clearly communicated to the public using myriad avenues (e.g. not peer review publication!). Recognizing well-founded fears among some individuals and groups of being used as guinea pigs for research (see Q&A of 6/7 for a few historic examples of how scientists in the US abused Black people in the name of science), community engagement in vaccine research, roll-out, and monitoring is necessary. Since Black and brown people have been disproportionately harmed by the coronavirus, they may be considered a priority group to receive vaccination. On the flip side, in the context of limited safety data, rolling out a vaccine first among people of color could easily be viewed as another way in which people of color are devalued. Johns Hopkins Center for Health Security’s Working Group on Reading Populations for COVID-19 Vaccination recently issued a set of guidelines to help policy makers work through these challenging issues.