People were not created equal, at least when the level of COVID-19 antibodies are measured among women and men who were infected and recovered and between those who were vaccinated and not vaccinated.

A joint study conducted by researchers from Tel Aviv University (TAU) and the Shamir Medical Center (Asaf Harofeh in the city of Beer Yaakov near Rishon Lezion) examined the level of antibodies in over 26,000 blood samples taken from COVID-19 convalescents, as well as vaccinated and unvaccinated individuals. 

A serological examination detects antibodies to the coronavirus and allows you to know most likely if you have been exposed to the virus Even if you haven’t experienced any symptoms. This is determined bya  simple blood test that examines whether there are lgG antibodies in the body for the coronavirus. The antibodies are created in the body after exposure to the virus and over time, they may vaccinate us against the virus in future exposures.

The serological results showed that the level of antibodies changes according to age groups, gender, symptoms, and time elapsed since vaccination. The study was published in Medrxiv, the online medical site publicizing preliminary reports of work that have not yet been certified by peer review. The item was entitled “Antibody response to SARS-CoV-2 infection and BNT162b2 vaccine in Israel.” 

The study was conducted by TAU’s Prof. Noam Shomron, head of the computational genomics laboratory at the university’s Sackler Faculty of Medicine and a member of the Safra Center for Bioinformatics and Dr. Adina Bar Chaim from the Shamir Medical Center. The data were collected by Dr. Ramzia Abu Hamad from the Shamir Medical Center, and analysis was conducted by Guy Shapira, a doctoral student at Shomron’s lab. 

The immune response of individuals who have received two doses of the Pfizer vaccine was shown to be much stronger than that of people who have recovered from COVID-19. In fact, the level of antibodies found in the blood of vaccinated persons was four times higher than that found in convalescents.

A difference was also found between vaccinated women and men, in the concentration of antibodies in the blood relative to both age and gender. In women, the level of antibodies begins to rise from the age of 51, and is higher than the levels found in men of similar age. This phenomenon may be related change in levels of the estrogen hormone, observed around this age, which affects the immune system. In men, a rise in antibody levels is seen at an earlier age, starting around 35. This may be related to changes in levels of the male sex hormone testosterone, and the effect on the immune system. 

In young adults, a high concentration of antibodies is usually the result of a strong immune response, while in older people it typically indicates overreaction of the immune system associated with severe illness. In general, young adults were found to have a higher level of antibodies sustained for a longer period of time compared to older vaccinated persons. A decrease of tens of percent was observed over time between the younger and very-old age groups

The team said that additional research is needed to get an in-depth understanding of the immune system’s response to COVID-19, recovery from the disease and the vaccine. “We hope that in the future we will be able to supply a reliable measure for the effectiveness of vaccination, correlated with age, gender and symptoms,” they wrote.