A single dose of vaccine acts as a “booster” for patients previously infected with COVID-19

Credit: torstensimon, Pinterest, CC BY 2.0

These are the results of research published as a research letter. LancetOf the 51 UK healthcare workers, about half had SARS-CoV-2 infections previously identified in the laboratory.

A single dose of Pfizer / BioNTech RNA vaccine The immune response to the virus was significantly enhanced compared to a single dose in people who were not previously given infection.. The enhanced response was at least an order of magnitude greater than after the traditional double inoculation schedule in previously uninfected individuals.

Researchers have found that while the findings add to the new context of COVID-19 immunology, they may influence current UK vaccination policies or provide a second booster vaccination through the NHS COVID-19 vaccination program. Warns that people should not be discouraged from booking.

However, they inform future vaccination strategies, including serological testing (also known as antibody testing) at the time of initial vaccination, and a second booster dose to previously uninfected individuals. It may be possible to prioritize. Researchers explain that such an approach may accelerate vaccine deployment by further expanding vaccine supply.

This study is a collaborative study by scientists at UCL, UK Public Health Services, Barts Health NHS Trust, Royal Free London NHS Foundation Trust, QMUL, and Imperial College London. Institute of Cardiovascular Science).

Professor Moon said: “These published peer-reviewed results show that health care workers previously infected with COVID-19 show a huge antibody response to the first vaccine dose that effectively acted as a boost.”

Prime / boost approach

Most approved COVID-19 vaccine platforms rely on a double dose approach (first primer followed by booster after a few weeks), Immune response Against peplomer on the surface of the virus. This includes the Pfizer and AstraZeneca vaccines currently being rolled out in the United Kingdom.

However, despite increasing evidence of the actual efficacy of the vaccine, the impact of previous SARS-CoV-2 infections on dosing regimens is unknown or still clear.

In the latest study, researchers looked at antibody data from healthcare professionals enrolled in an ongoing observational study (COVIDsortium).

All participants underwent weekly PCR and serology tests for 16 weeks from the date of the first UK lockdown in March 2020. From a sample of 51 participants, 24 had previous COVID-19 infections confirmed by laboratory PCR tests. Participants received a single dose of Pfizer / BioNTech mRNA vaccine and blood tests were analyzed 3 weeks later.

After a single dose of Pfizer vaccine, participants produced antibodies to the peaplomer. In pre-infected individuals, levels of peplomer antibody were similar to the measured peak levels seen in individuals with mild SARS-CoV-2 infection.

However, previously infected individuals produced higher levels of antibody against peplomer after a single dose compared to previously uninfected individuals, indicating a significantly enhanced antibody response. I will.

Twenty-four blood analyzes showed that antibody response (anti-S response) increased by an average of 140-fold after infection and before the first vaccination, compared to peak antibody levels before vaccination after a single dose of vaccine. Shown.

Professor Mahdad Noursadeghi (UCL Infection and Immunology), a leader in UCL immunology for this study, added: “Previous infections in this group date back to the beginning of the London epidemic. Such boosting effects emphasize the lifespan of immune memory against this infection, as booster vaccines maintain high levels of immunity in the future. Increases confidence that it may be an effective method of. “

Research limits

Researchers found that these findings were associated with infectious disease findings that were confirmed in the laboratory only at this stage: the amount of virus that caused the initial infection (viral load), the age of the participants, and detailed health. Of those infections, it emphasizes that it does not consider variables such as condition and severity.

This study was also limited to a small group of Pfizer / BioNTech mRNA vaccines. Health care workers With or without infection confirmed in the lab. At this stage, it cannot generally be applied to other groups (elderly, people with underlying health, etc.) or other vaccines.

Their authors explain that the findings add to the growing situation of immunological protection against SARS-CoV-2 and can inform other programs around the world where vaccine supply may be restricted. doing.

In fact, laboratory-based tests can be used to screen patients for antibodies to the spike protein prior to initial vaccination. This is by reallocating the vaccine dose and prioritizing patients who may benefit more from the second dose compared to those who responded adequately to the single dose. Helps accelerate deployment.