These 3 Factors Impact COVID-19 Vaccine Antibody Response

These Factors Impact COVID-19 Vaccine Antibody Response

Recent study suggests three factors inhibit the immune response after COVID-19 vaccination.

While the COVID-19 vaccines are the world’s first mRNA vaccines, they still work similarly to other vaccines in that they elicit an immune response leading to protection. Now, new research suggests three factors may inhibit this immune response.

The study specifically pertains to the Pfizer-BioNTech mRNA vaccine. The participants included a total of 248 healthcare workers (158 women and 90 men). Researchers analyzed the participants’ antibody titers seven days after they received the second dose of the vaccine.

The participants were assigned to receive the priming dose at baseline and booster dose at day 21. Blood and nasopharyngeal swabs were collected at baseline and seven days after the second dose of the vaccine.

COVID-19 Vaccine & Antibody Response

The findings revealed three factors impaired immune response:

1. Weight. A strong correlation of BMI classes with antibody titers was noticed: humoral response was more efficient in the group with under and normal weight versus the group with pre- and obesity participants.

2. Age. The antibody titer was found to be higher in younger participants.

3. Sex. The antibody titer was also found to be higher in female participants.

According to the authors, “The findings imply that females, lean, and young people have an increased capacity to mount humoral immune responses compared to males, overweight, and the older population.”

As the study is a preprint, more peer-reviewed research is needed to incorporate new guidelines into clinical practice. For example, the authors note, “If the data is confirmed by larger studies, giving obese people an extra dose of the vaccine or a higher dose could be options evaluated in these populations.” There is also need of further research to evaluate whether or not the same populations inhibit immune response with the Moderna or Johnson & Johnson COVID-19 vaccines.

Typical Immune Response to Vaccinations

Outside of the COVID-19 vaccines, there is substantial variation between individuals’ immune response to any vaccination. These include intrinsic factors (age, sex, weight, etc.) as well as extrinsic factors (pre-existing immunity, infections, pharmacological interactions, etc.). Furthermore, environmental factors (geographic location, family size, exposure to toxins, etc.), behavioral factors (smoking, alcohol consumption, exercise, etc.), and nutritional factors influence how individuals respond to vaccines.

Myths About the COVID-19 Vaccine & Antibody Response

Unfortunately, several myths are circulating regarding the COVID-19 vaccine. As a healthcare professional, it is important to ease your patients’ anxieties surrounding the vaccines and provide accurate information.

Myth 1: The COVID-19 vaccine will make you sick with COVID-19.

None of the authorized and recommended COVID-19 vaccines in the United States contain the live virus that causes COVID-19. This means the vaccine cannot make you sick with COVID-19.

However, you can feel ill after receiving the COVID-19 vaccine. Symptoms include fever, chills, fatigue or headache. These symptoms are normal and are actually a sign that the body is building protection against the virus.

Myth 2: Immediately following vaccination, you have immunity against COVID-19.

It typically takes a few weeks for the body to build immunity after the vaccination. This means it is possible to be infected with the virus just after vaccination.

Myth 3: I will test positive for COVID-19 after getting the vaccine.

None of the authorized and recommended COVID-19 vaccines in the United States can cause positive COVID-19 viral test results. It is possible to test positive on an antibody test, but not a viral test.

Myth 4: The COVID-19 vaccine will alter my DNA.

The COVID-19 mRNA vaccines do not alter DNA in any way. The mRNA vaccines trigger an immune response, but the mRNA from the vaccine never enters the nucleus of a cell.

Learn More: COVID-19 Vaccine Information for Healthcare Providers


1. Clinical Microbiology Reviews Mar 2019, 32 (2).

2. CDC: Myths and Facts about COVID-19 Vaccines retrieved March 9, 2021.

This article was written by Jami Cooley

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