When Can We Expect a COVID-19 Vaccine?

As of March 15, 58 deaths due to COVID-19 have occurred in the U.S. according to the CDC. At a press conference this past week, President Trump announced that several companies are attempting to work in the private sector to develop a vaccine. The National Institutes of Health (NIH) announced today that they are beginning their first clinical trial testing a potential vaccine. So when can we expect to have a vaccine?

Presently, the COVID-19 vaccine is in Phase 1 at the Kaiser Permanente Washington Health Research Institute (KPWHRI) in Seattle, Washington. During this phase, researchers are recruiting 45 otherwise healthy adults to receive the vaccine and be monitored for 6 weeks. The first participant has received the vaccine. Although they believe the vaccine will work, they must recruit a variety of people in order to determine 1.) the correct dosage, 2.) side effects, and 3.) demographic differences.

Researchers do this through conducting an experiment with 15 people in each dosage condition. One group will receive a 25mcg dose, while the other groups receive 100mcg and 250mcg, respectively. During follow-up visits, the research team will make note of the common side effects, as well as any novel side effects which occur. The team will also take blood samples to monitor the immune system’s response to the vaccine. The virus cannot be detected trough the blood sample, but researchers can measure the white blood cell count which indicates how active someone’s immune system is in response to some illness. The immune system should initially respond by producing more white blood cells in an attempt to learn the pattern of the illness. The immune system should then return to normal production of white blood cells. Researchers need to determine if this vaccine is activating the immune system and then determine how long it takes for their participant’s immune system to return to normal.

Since this first phase will take 6 weeks to complete, we can’t expect to have a vaccine in the hands of doctors around the world for at least 2 months. This phase, if successful, is only the beginning since the vaccine will need manufactured for global distribution. Fortunately, companies appear to be willing to accelerate the otherwise time consuming and expensive process in order to stop this pandemic. Multiple governments have also offered funding and resources to assist as well. Depending on the complexity of the vaccine, the monetary cost can range from $500M-700M to manufacture (Plotkin et al., 2017). The manufacture also involves skilled labor and advanced equipment. Some countries do not possess these resources, so vaccines will need to be produced in technologically advanced societies and imported into less developed countries. The manufacture and importation of the vaccine globally can take months.

Beyond the time to manufacture the vaccine, administration of it will take more time. As we see with the flu vaccine or other common vaccines, there are people who push back against it often citing that it causes autism or makes people sick. Instead, these individuals rely on “herd immunity.” Herd immunity means that others around are vaccinated, protecting others who cannot receive the vaccine. Those unable to take the vaccine are those that are too young or are immune-compromised in some way. Herd immunity as it was initially conceptualized does not include conscious objectors to vaccinations, only individuals which cannot otherwise receive the vaccine. By individuals rejecting the vaccine for other reasons, this can stress the herd and make the proportion of vaccinated to unvaccinated too small. Each disease or illness is assigned a herd immunity threshold which indicates how well the herd protects these individuals. For a disease like measles, the CDC believes that herd immunity is 92-95% effective. For the flu, the statistics are not as optimistic. Herd immunity for the flu is only 33-44% protective. This is likely due to the nature of the flu which is spread via airborne droplets which do not necessarily need a host to carry the illness to someone else. Additionally, the flu has multiple strains.

COVID-19 bares more resemblance to the flu than measles as we are presently aware. Thus, we can expect herd immunity to be only so effective. Thus, the government and healthcare professionals will likely encourage everyone to get the vaccine when it comes out. The rush of people to get the vaccine will lead to long lines, too many patients for administrators, and complications. Administering the vaccine and finding enough staffers can take up to a month to vaccinate a large portion of the public.

The existence of the vaccine is crucial to managing the death toll of this virus, but it will likely take a while. Once the vaccine is developed, other issues will likely arise as we have already seen with vaccinations: Can the government force vaccinations on the public?

- Jacky Anderson

References:

CDC. “Understanding How Vaccines Work.” https://www.cdc.gov/vaccines/hcp/conversations/downloads/vacsafe-understand-color-office.pdf

NIH. (2020) “NIH clinical trial of investigational vaccine for COVID-19 begins.” National Institutes of Health. https://www.nih.gov/news-events/news-releases/nih-clinical-trial-investigational-vaccine-covid-19-begins

Plotkin, S., Robinson, J.M., Cunningham, G., Iqbal, R., & Larsen, S. (2017). The complexity and cost of vaccine manufacturing – An overview. Vaccine, 35(33), 4064-4071. doi: 10.1016/j.vaccine.2017.06.003