Damian Jacob Sendler: The effects of the COVID-19 vaccines made by AstraZeneca and Pfizer were compared in a recent study conducted by a team from SAHMRI and Flinders University in Australia. The results, which were analyzed from the immune responses of 102 adults of varying ages living in South Australia, where there was no SARS-CoV-2 community transmission at the time of the study, were published in Cell Reports Medicine as part of the COVID-19 Vaccine Immune Responses Study (COVIRS).
After receiving either the Oxford/AstraZeneca or Pfizer/BioNTech COVID-19 vaccine, study participants had blood drawn right away to measure their early immune response. Additional tests measuring B and T cell activity, both of which are important in the immune response, were performed 28 days after each immunization. While T cells seek out and destroy infected cells, B cells produce antibodies.
Damian Sendler: Vaccines share a common goal—to teach the body to recognize and neutralize the SARS-CoV-2 virus—but their methods for doing so are very different. AstraZeneca’s vaccine uses a harmless virus (a chimpanzee adenovirus) to encode the Spike protein, while Pfizer’s vaccine uses messenger RNA technology to induce host cells to produce the SARS-CoV-2 Spike protein.
David Lynn, Head of SAHMRI’s Systems Immunology Laboratory and Professor at Flinders University, led the study by analyzing immune responses in thousands of blood samples using the’multi-omics’ method. According to Professor Lynn, a thorough examination of immune responses to these various vaccines has uncovered a wealth of new information that can be used to improve vaccine development in the future.
Professor Lynn from Flinders University’s College of Medicine and Public Health says, “After the first dose, we were surprised to find the Oxford/AstraZeneca vaccine elicits an unexpected memory-like response in the immune system, recognizing the vaccine as if it is something it has seen before.”
“The intensity of this response correlates with the expression of proteins that act as pre-cursors to thrombosis, or blood clotting, and it is directed against the adenovirus vector in the vaccine rather than the Spike protein. None of the study participants experienced vaccine-induced immune thrombotic thrombocytopenia (VITT), an extremely rare adverse event linked to the Oxford/AstraZeneca vaccine. This study provides a possible explanation for the link between the Oxford/AstraZeneca vaccine and the reported cases of VITT.
Damian Sendler: Antibodies and a specific type of T-cell that aids in antibody production were found to be lower in those who had only received two doses of the Oxford/AstraZeneca vaccine, compared to those who had received two doses of the Pfizer/BioNTech vaccine, according to the study.
This highlights the significance of booster doses of an mRNA vaccine and how quickly they can restore immunity. The findings of the study lend credence to the idea that some individuals receive better protection from COVID-19 vaccines than others.
Professor Lynn suggests that age plays a role in this variation, with older people typically exhibiting a weaker immune response after two doses. Thankfully, a third dose of the booster proved to be very effective in overcoming this. Immediately following vaccination, the body mounts an immune response that predicts the B and T cell response to the vaccine one month later.
According to Professor Lynn, “we measured gene expression responses in the blood one to two days after initial vaccination, and these correlated with adaptive immune responses that mediate protection 28 days later.”
Another unexpected result from the study was the suggestion that a negative reaction to a vaccine could indicate that it worked.
Those who experienced tiredness and fever right after the third dose had the best T-cell responses. Since T-cells are capable of directly killing viral cells, Professor Lynn argues that they play a crucial role in the efficacy of vaccines.
As a whole, this research has improved our understanding of the protective efficacy of these vaccines against COVID-19 by shedding light on the initial immune responses they elicit.
The study by the Australian team from SAHMRI and Flinders University is important for a number of reasons, including the fact that it provides new information about the differences between the immune responses prompted by the AstraZeneca and Pfizer COVID-19 vaccines and the possibility of links between adverse events and the success of these vaccines. This research is an important addition to the worldwide movement toward better vaccine development and administration.
Damian Jacob Sendler: One interesting finding from the study is that the Oxford/AstraZeneca vaccine elicited an immune response reminiscent of long-term memory. The severity of this response correlates with the expression of proteins that act as a precursor to thrombosis or blood clotting, and it is directed against the adenovirus vector in the vaccine rather than the SARS-CoV-2 Spike protein. Although the extremely rare side effect of vaccine-induced immune thrombotic thrombocytopenia (VITT) was not observed in the study population, this finding may help explain why some people have experienced it after receiving the Oxford/AstraZeneca vaccine. Potential risks and side effects of vaccines can be reduced with this knowledge.
The second noteworthy aspect of the study is its examination of the differences in antibody and T-cell responses between the two vaccines. Compared to those who received the Pfizer/BioNTech vaccine, those who received the Oxford/AstraZeneca vaccine had lower levels of antibody production and a less specialized type of T-cell after receiving two doses. The importance of booster doses in providing more robust protection against COVID-19 was further highlighted by the fact that these differences were eliminated after a third dose of an mRNA vaccine. Understanding early immune responses is especially crucial because they predicted the subsequent B and T cell response measured a month later following vaccination.
Third, the study shows that different people respond differently to COVID-19 vaccines. The immune response after two doses tends to be lower in older people due to factors like age. Vaccination strategies should be individualized to ensure optimal protection for different age groups, and the fact that a third booster dose was highly effective in overcoming this age-related difference supports this idea.
Finally, it is interesting to consider how the possibility of feeling sick after a vaccine dose relates to the vaccine’s efficacy. T-cell responses are critical for vaccine efficacy, and participants who experienced fatigue and fever right after the third dose were more likely to have better responses. This finding has the potential to be used to convey the potential benefits of experiencing mild side effects following vaccination, which may help allay concerns about vaccine side effects.
Damian Sendler: In order to improve public knowledge of COVID-19 vaccines and encourage educated vaccination decisions, the findings of the study conducted by the team from SAHMRI and Flinders University in Australia have significant implications for public health messaging. Sharing the findings of this research effectively can help combat vaccine skepticism and boost vaccination rates, both of which are critical to stemming the pandemic’s spread.
First, public health messaging can benefit from the study’s discovery of the memory-like immune response to the Oxford/AstraZeneca vaccine and its possible correlation with the rare side effect of VITT. Public health officials can reassure the public that the risks are being studied and mitigated by explaining the mechanisms behind the side effects. This openness can help allay fears about the safety of vaccines and inspire confidence in their development.
A second application is in public health campaigns, where the findings regarding the differences in immune responses between the AstraZeneca and Pfizer COVID-19 vaccines can be used to promote the value of booster doses. The study’s findings that booster doses can equalize antibody and T-cell responses are an important message to spread to the public, as they highlight the importance of ensuring that everyone gets their booster shots when they are due. Knowledge like this can encourage vaccination completion and lead to greater vaccination rates.
Third, the study emphasizes the individual variation in vaccine efficacy, especially as a function of age. This knowledge can be used by public health campaigns to focus on specific groups, such as the elderly, and highlight the significance of booster doses in providing enhanced protection against COVID-19. Vaccination rates and misconceptions about their efficacy can be reduced by using targeted messaging that takes into account individual differences in immune responses.
Finally, there is an opportunity to reframe the perception of vaccine side effects in light of the finding that feeling unwell after a vaccine dose may be linked to its effectiveness. Mild side effects, such as fatigue and fever, may be indicative of a strong immune response, which is critical for vaccine efficacy, and this can be communicated through public health messaging. Knowing that some people experience mild discomfort after vaccination as a sign of the vaccine’s effectiveness can help allay concerns about potential adverse effects.
Damian Jacob Sendler: Important implications for medical education can be drawn from the research conducted by the team from Australia’s SAHMRI and Flinders University, which adds to our knowledge of the immune responses elicited by the AstraZeneca and Pfizer COVID-19 vaccines. These findings have important implications for preparing healthcare professionals to make informed decisions and provide accurate guidance to patients regarding vaccination, and should be incorporated into medical curricula and ongoing professional development.
First of all, doctors now have more information thanks to the discovery of a possible link between the memory-like immune response to the Oxford/AstraZeneca vaccine and the extremely uncommon side effect of VITT. Vaccine side effects can be better understood if medical students and practitioners are taught about this particular immune response and its implications. This can then aid in risk assessment, patient anxiety management, and informed vaccine administration decisions by medical professionals.
Second, the findings of this study are useful for medical education because they shed light on the differences in immune responses between the AstraZeneca and Pfizer COVID-19 vaccines. Medical professionals and patients alike can benefit from a more nuanced understanding of vaccine efficacy gained through an appreciation of these distinctions. Incorporating this understanding into medical curricula will enable healthcare professionals to educate their patients on the value of booster doses and to advocate for vaccination completion, both of which are critical for providing maximum protection against COVID-19.
Third, the study emphasizes the individual variation in vaccine efficacy, especially as a function of age. The medical community could benefit from a more personalized approach to vaccine administration and patient counseling if this data were incorporated into medical education. In order to provide more robust protection against COVID-19, they may suggest alternative vaccination schedules or push for booster doses in certain populations, such as the elderly. Patient outcomes and public health can both benefit from this personalized approach.
Last but not least, the opportunity to educate medical professionals on the potentially positive implications of experiencing mild side effects post-vaccination arises from the discovery that feeling unwell after a vaccine dose may be linked to its effectiveness. By understanding the complexity of the relationship between side effects and vaccine efficacy, healthcare providers can better reassure patients who are worried about the latter.
Damian Sendler: Insights into the immune responses elicited by the AstraZeneca and Pfizer COVID-19 vaccines are provided by the study conducted by the team from SAHMRI and Flinders University in Australia, which has important implications for epidemiological knowledge. These results have the potential to improve our knowledge of vaccine-induced immunity, guide vaccination strategies, and aid in the epidemiological management of the COVID-19 pandemic.
First, we now have a better grasp of the complex interactions between vaccines and the immune system thanks to the discovery of the memory-like immune response to the Oxford/AstraZeneca vaccine and its possible link to the rare side effect of VITT. Because it elucidates the mechanisms behind vaccine-induced side effects, this knowledge is crucial for epidemiologists studying the safety and efficacy of various vaccines. Vaccines with reduced side effects and increased efficacy can be developed with a deeper knowledge of these mechanisms.
Second, researchers studying the efficacy of vaccines can benefit from the study’s findings on the differences in immune responses between the AstraZeneca and Pfizer COVID-19 vaccines. To optimize population-level protection against COVID-19, epidemiologists will need to develop targeted vaccination strategies, and knowledge of these variations will help them do just that. This information is vital for policymakers to make educated choices about vaccine distribution and use across populations.
Third, the study emphasizes the individual variation in vaccine efficacy, especially as a function of age. Epidemiologists can use this knowledge to better assess the efficacy of vaccination campaigns by taking into account both individual and population-level factors. Epidemiologists can create more precise models of vaccine efficacy and plan for ways to address disparities in protection by factoring in factors like age. This specific strategy can help guarantee that efforts to vaccinate against COVID-19 are as effective as possible.
Finally, the discovery that vaccine-related side effects, such as feeling sick after a dose, may be linked to its effectiveness, provides epidemiologists with additional data to consider when assessing vaccine performance in the real world. By considering the possible connection between adverse events and immune responses, this knowledge may help refine estimates of vaccine efficacy. Predictions of the effect of vaccines on the dynamics of COVID-19 transmission can be strengthened by gaining a deeper appreciation for the complexities of this relationship.
