Can I Still Get COVID-19 After I’m Vaccinated?
Nowadays many people are trying to understand if it is safe to return to all the activities, they have refrained from due to the pandemic. However, with the emergence of different variants and the rise in the number of breakthrough infections, people are increasingly concerned about the level and the durability of the immunity they get after vaccination. Indeed, breakthrough infections seem more common now that more transmissible COVID-19 strains such as Omicron are spreading rapidly around the globe and the immunity may be declining among those who got vaccinated months ago. Here is what to know about breakthrough infections.
What is a breakthrough infection?
A breakthrough infection is an infection with a bacteria, virus, or other germ that emerges after vaccination for that specific pathogen. In the case of COVID-19, breakthrough infections refer to infections with SARS-CoV-2 that emerge in fully vaccinated individuals.
The occurrence of breakthrough infections among a small portion of vaccinated people is expected in the case of any pathogen and vaccine, because no vaccine offers complete protection from for every person at every point in time.
The odds of a breakthrough infection happening to you depends on several factors including your age, health conditions, whether you have had a previous COVID-19 infection, the time of your previous infection and the severity of your symptoms.
Research shows that people with weakened immune systems due to certain medical conditions and treatments and people in older age groups have a greater risk of developing a breakthrough infection.
The emergence and frequency of breakthrough infections is also shaped by the evolution and circulation of SARS-CoV-2. A US-based study conducted on over 4 million fully vaccinated individuals has found that between January 17 and August 21, 2021, the ratio of breakthrough infections was 1/5000. However, more recently, some populations have exhibited rates of breakthrough infections as high as 1/100. Experts argue that this rise in frequency may be due to the circulation of more transmissible variants such as Omicron. Another factor responsible for the growing frequency of breakthrough infections may be that people are dropping the other interventions such as using masks and social distancing. Overall, the frequency of breakthrough infections grows when the virus starts to spread more rapidly and widely.
Can I transmit the virus even if I am fully vaccinated?
Once you are infected, while the vaccine may prevent you from experiencing serious symptoms, research shows that you can still replicate and transmit SARS-CoV-2. A peer-reviewed study1 conducted on 162 Delta-infected individuals and their 231 household contacts demonstrated that a quarter of both vaccinated people and unvaccinated people transmit the virus to people in their households.
A larger UK-based study2 of 108,498 adult index cases and 146,243 adult contacts also assessed the transmission rate of the virus from the newly vaccinated people to their contacts as one in a quarter. However, around three and a half months post vaccination, people vaccinated by the AstraZeneca vaccine were about as likely to transmit the virus as unvaccinated people. Those who were vaccinated by the Pfizer vaccine was around 80% as likely, and the rate was observed to grow with time.
The impact of vaccination
Vaccination is still one of the most effective strategies in reducing infection, hospitalization, and death.
First, although they do not offer %100 protection, vaccines can protect you against getting infected altogether. Moreover, even if you get infected, vaccines are very effective in preventing you from severe illness, long-term symptoms, hospitalization, and death regardless of the variant. Research shows that compared to unvaccinated people, those who are fully vaccinated were 6 times less likely to get infected with SARS-CoV-2 and 11 times less likely to die if they get it. Another study demonstrated that vaccination reduces the risk of developing long-term symptoms of COVID-19 such as kidney damage, heart issues, breathing issues, along with loss in the sense of smell and taste. Thus, while breakthrough infections may cause mild to moderate symptoms, especially for people who have a healthy immune system, the risk of experiencing severe illness and long-term health issues is very low.
Vaccines also provide a much higher immune memory than a previous infection by SARS-CoV-2. Although much is yet to be known about the level, form, and duration of immunity that vaccines and natural infections provide against SARS-CoV-2, experts suggest that vaccines provide a very focused and potent immune response by generating a big spike in the number of neutralizing antibodies. These antibodies are every effective in preventing the virus from replicating and casing an infection. Indeed, a study has found that fully vaccinated people were 5 times less likely to be hospitalized with an infection than unvaccinated people with natural immunity due to a previous COVID-19 infection.
Further, vaccines may reduce the transmission of SARS-CoV-2. As mentioned above, vaccination may curb the spread of the virus by reducing the risk of infection altogether. Still, in the case of an infection, if you are vaccinated, there may be less density of the virus in you, and you may shed you the virus for a relatively shorter period of time than if you were unvaccinated. By limiting viral density and shedding time, vaccines may reduce the risk of transmission of COVID-19 from one person to the next.
Much is yet unknown about the duration of the immunity provided by COVID-19 vaccines. Moreover, the correlation between antibody levels and protection remains unclear. Still, while there is some evidence to suggest that their protection against infection declines to some degree over time, vaccines prove to be very effective in preventing severe illness, hospitalization, and death.
Research suggest that boosting could restore and/ or improve the protection of vaccines against infection. If the protection of your vaccines has begun to wane in time, getting a supplementary dose of the COVID-19 vaccine may prolong your immunity, reduce the risk of a breakthrough infection, prevent the development of serious symptoms.
Finally, it should be remembered that all safety precautions such as mask wearing, hygiene, and physical distancing contribute to our level of protection against SARS-CoV-2 together with vaccination. To curb the spread of SARS-CoV-2, we should incorporate these precautions alongside vaccination.
- Eyre, D. W., Taylor, D., Purver, M., Chapman, D., Fowler, T., Pouwels, K., Walker, A. S., & Peto, T. E. (2021). The impact of SARS-CoV-2 vaccination on Alpha and Delta variant transmission. medRxiv. https://doi.org/10.1101/2021.09.28.21264260
- Antonelli, M., Penfold, R. S., Merino, J., Sudre, C. H., Molteni, E., Berry, S., Canas, L. S., Graham, M. S., Klaser, K., Modat, M., Murray, B., Kerfoot, E., Chen, L., Deng, J., Österdahl, M. F., Cheetham, N. J., Drew, D. A., Nguyen, L. H., Pujol, J. C., . . . Steves, C. J. (2021). Risk factors and disease profile of post-vaccination SARS-CoV-2 infection in UK users of the COVID Symptom Study app: a prospective, community-based, nested, case-control study. The Lancet Infectious Diseases, 22(1), 43–55. https://doi.org/10.1016/s1473-3099(21)00460-6