Many media outlets and even public health experts are becoming enthusiastic about vaccines designed to prevent or mitigate COVID-19 infections. Most people hope that an effective COVID-19 vaccine will help us participate again in school, business and social gatherings. However, we probably will have to wait quite a while before those hopes are realized.
COVID-19 Vaccine Development Proceeding at “Warp Speed:”
Scientists usually take years to develop a vaccine against a brand-new disease. An unusual public-private partnership dubbed Operation Warp Speed aims to reduce development time dramatically. Many government agencies, including the Department of Health and Human Services (HHS), including the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), the National Institutes of Health (NIH), and the Biomedical Advanced Research and Development Authority (BARDA), and the Department of Defense (DoD) have provided support and funding to pharmaceutical firms. Their goal is 300 million doses of vaccine against SARS-CoV-2, the virus that causes COVID-19, ready in January 2021. This is extremely ambitious.
Where Do We Stand With a COVID-19 Vaccine?
Messenger RNA (mRNA) vaccines have not been used before but have triggered a robust immune response in early trials. They are now in phase 3 trials, which are designed to determine how effective such vaccines will be in real life. Both Moderna and Pfizer are developing mRNA vaccine candidates under the auspices of Operation Warp Speed (JAMA, July 6, 2020).
Viral Vector Vaccine:
Some vaccines use a living virus that has been “attenuated” so that it no longer causes illness to carry the antigen into the body and alert the immune cells to defend against it. Such viruses can replicate, but they don’t make people sick. Hopefully, though, they will trigger an effective immune response against SARS-CoV-2. Operation Warp Speed is funding such a COVID-19 vaccine from Merck Sharp & Dohme.
Spike Protein Vaccines:
Two other vaccine candidates use carrier viruses that can’t replicate themselves. AstraZeneca and Johnson & Johnson are using Operation Warp Speed funding to develop such vaccines that present the coronavirus spike protein to immune cells in the body. Like the mRNA vaccine, this relatively new technology has not been widely employed before now.
What Is the Expected Outcome?
First, tests must demonstrate that a vaccine candidate effectively prevents COVID-19 before it can be used. Equally important, we must have assurance that the vaccine is safe and does not cause unacceptable side effects. Operation Warp Speed is currently testing these vaccines for effectiveness and safety.
Even after one or more effective vaccines are developed, however, it will take time to distribute them widely. Rolling vaccinations out to everyone who needs them will challenge public health authorities severely.
Experts also worry that expectations may be unrealistic. It takes weeks for the immune system to react to a vaccination. And some of the vaccine candidates may well require multiple doses over several weeks or months.
In addition, vaccines are rarely 100% effective. A vaccine that offers even 50% protection would be beneficial, but it won’t take the world back to a pre-pandemic situation. Even after companies announce the launch of new vaccines, people will have to continue taking precautions against infection for the foreseeable future.