Today, countries across the globe are in a rush to vaccinate their populations against the SARS-Cov-2, the virus causing COVID-19. Considering the fact that there are significant numbers of people who have already had the virus and developed immunity for some time, there are questions regarding the immune response of the body to the administration of the vaccine. It has been suggested that in individuals who had immunity to COVID-19 after getting the virus, the immune response would be stronger from only the first dose.
As of now, the US is predominantly using Moderna and Pfizer-BioNTech, both of which require two doses of the vaccine that are administered several weeks apart. Vaccines are designed to safely deliver an immunogen, which is an antigen that is able to elicit a response from the immune system, in order to train it to recognize the dangerous pathogen when it is encountered. The immunogen activates the CD4+ helper T cells, which, in turn, stimulate B-cells to produce neutralizing antibodies to target the virus and the CD8+ cytotoxic T cells to recognize and kill the cells that are infected by the virus. The choice of an immunogen for COVID-19 vaccines will influence the type of immune response that is induced, as well as safety, development and production time, costs and access to vaccines.
It is notable that the large majority of COVID-19 vaccines are designed for a two-dose administration due to particular expectations of the immune system. Two-dose vaccination, which is also referred to as ‘prime-boost,’ works by mimicking the natural immunity of a body. The first dose is intended to prime immunological memory while the second dose solidifies it (Voysey et al., 2021). After the first dose is administered, an individual’s immune system needs some time to generate the appropriate response and to create memory cells that will be able to recognize the pathogen once encountered. According to the findings of Voysey et al. (2021), a larger interval between the two doses of the vaccine may facilitate a stronger immune response as compared to the shorter interval, although mostly in the AstraZeneca trial.
Besides, it is essential to mention the research that showed that individuals that have already had COVID-19 are more likely to develop strong immunity after the first vaccine. In their study, Ebinger et al. (2021) compared the levels of antibodies in people with prior COVID-19 infection to those who never had the virus. Across the sample population involved in the study, those previously infected by the virus had higher levels of antibodies after vaccination (Ebinger et al., 2021). Notably, the immunity levels before the vaccination were on a similar level among previously infected and uninfected individuals. However, Ebinger et al. (2021) found that antibody levels in previously infected people after their initial vaccination were as high as those of uninfected individuals after their second shot.
Therefore, it appears that a booster dose can be administered to previously infected individuals to gain the same benefit as the two doses given to individuals without prior infection. However, more research is needed to be completed before the strategy can be deployed in the general population. Besides, larger sample populations than Ebinger et al. (2021) used are needed to account for the individual variation in immune responses to vaccinations against COVID-19. When it comes to the timeframe during which the COVID-19 vaccine lasts, more research is needed to study the topic. At this time, research showed that the vaccinated individuals had very strong immunity to the virus, and it looks like it will last for a while. However, scholars need to follow up on the immune levels over time.
Considerations of the impact of the COVID-19 on preventing the Delta variant are also necessary. Vaccine makers claim that their vaccines do provide immunity against the Delta variant of the virus, and if the infection takes place, the illness should not be severe. Besides, experts agree that in fully vaccinated individuals, there is a very low chance of hospitalization or mortality. With many vaccines, individuals do not have just one antibody that develops as a response to it, and there are different antibodies that work in several areas. Even if there are some changes, there are also other areas against which the immunity responds.
To conclude, vaccinations are currently the most valuable and sustainable methods to help people develop immunity to the COVID-19 virus. With the help of vaccinations, the body produces the necessary immunogens that act as protectors against the disease and significantly lower the chances of disease development and accompanying exacerbations. Even though vaccines have side effects, such as the possibility of a severe allergic reaction, the reported cases of significant exacerbations are low in number. The known and potential benefits of vaccinations outweigh the known and possible risks, including severe heart issues or allergic reactions. Because of this, it is recommended for the entire adult population to get vaccinated against COVID-19 to have more opportunities for socializing, travel, and more.
References
Ebinger, J. E., Fert-Bober, J., Printsev, I., Wu, M., Sun, N., Prostko, J. C., Frias, E. C., Stewart, J. L., Van Eyk, J. E., Braun, J. G., Cheng, S., & Sobhani, K. (2021). Antibody responses to the BNT162b2 mRNA vaccine in individuals previously infected with SARS-CoV-2. Nature Medicine, 27(6), 981–984. Web.
Voysey, M., Costa Clemens, S. A., Madhi, S., Weckx, L., Folegatti, P., Aley, P. … Pollard, A. (2021). Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials. The Lancet, 397(10277), 881-891. Web.