The Oxford-AstraZeneca COVID-19 vaccine is poised to be globally discontinued, almost 3.5 years after its initial authorization. The vaccine’s discontinuation has attracted attention due to its notorious reputation. However, what is the underlying reason for this decision? It is not as sensational as some may imply.

As per a statement observed by the BBC, the decision was made for commercial reasons due to an excess of updated vaccines that has resulted in a decrease in demand.

Viruses have the ability to undergo mutations and evolutionary changes, and this holds true for SARS-CoV-2, the virus responsible for causing COVID-19. Consequently, a wide array of distinct variations has emerged, prompting certain vaccine manufacturers to develop revised vaccines specifically designed to combat these variations.

Nevertheless, AstraZeneca has not taken the same action. Professor Adam Finn from the University of Bristol stated to the Science Media Centre (SMC) that this implies that the vaccine, currently known as Vaxzevria, is likely significantly less efficacious than its initial effectiveness.

Therefore, it is highly unlikely that there is any economic justification for the ongoing production and distribution of the vaccine. This is likely the primary factor influencing the company’s decision to cease manufacturing and selling it.

The company has emphasized the effects of Vaxzevria since its implementation. The statement indicated that independent estimates showed that more than 6.5 million lives were preserved solely in the initial year of implementation. “Governments worldwide have acknowledged our endeavors and consider them to be a crucial element in bringing an end to the global pandemic.”

However, the vaccine did encounter some issues. In 2021, multiple countries halted the use of Vaxzevria as a precautionary measure due to reports of individuals experiencing a rare condition called thrombosis with thrombocytopenia syndrome (TTS) after receiving the vaccine.

The incidence of vaccine-induced TTS, however, has been determined to be significantly low. According to data from the UK, the likelihood of developing it after receiving the vaccination is estimated to be approximately 4 cases per 1 million individuals.

A comprehensive study of more than 29 million individuals revealed that contracting COVID-19 carries a significantly higher likelihood of developing blood clots compared to receiving the AstraZeneca vaccine.

“When considering our actions, we must always weigh the potential harm against the potential benefits. During the height of the pandemic, the AZ vaccine provided greater benefits than harm. However, now there are more effective and safer options available,” stated Professor Jonathan Ball, Deputy Director of the Liverpool School of Tropical Medicine, in an interview with the SMC.

“Maybe its relevance has diminished,” commented Dr. Michael Head, a global health researcher. The Oxford AstraZeneca vaccine has been instrumental in the global pandemic response for the majority of countries.

The World Health Organization (WHO) initiated its global vaccination program in 1974 with the aim of ensuring universal access to vaccines for children worldwide. A recent study indicates that vaccination has had a substantial effect on public health over the past 50 years, resulting in the prevention of millions of deaths.

Initially, the Expanded Programme on Immunization (EPI) by WHO aimed to vaccinate all children against seven diseases, including the now-extinct smallpox. However, the program has now been extended to cover 14 different pathogens.

The recent study analyzed the effects of the vaccines for these diseases on both local and worldwide public health from the start of the EPI in June 1974 until its 50th anniversary in 2024.

These estimates were obtained through the application of mathematical and statistical modeling to determine three important metrics: the quantity of prevented deaths, the amount of gained life-years, and the duration of improved overall health.

According to the findings of the 22 models combined, global vaccination efforts over the past 50 years have had a significant effect. It is estimated that immunization has saved approximately 154 million lives since 1974, replacing death with an average of 66 years of good health per person.

The program’s most significant influence in terms of age seems to be on the youngest members of society. Modeling analysis revealed that out of the estimated 154 million deaths that were prevented, 101 million were specifically among infants aged less than one year. Additionally, it was indicated that vaccination accounted for 40 percent of the decrease in worldwide infant mortality, making it the primary factor in that reduction.

Although all of the vaccines examined had an effect, the measles vaccine had the most notable influence, despite the recent resurgence of measles.

“Measles vaccination contributed to 60% of the overall benefits of vaccination over the span of 50 years, making it the primary factor in saving lives,” stated Dr. Andrew Shattock, the leader of the study.

The authors assert that the results serve as evidence of the potential that can be realized through collaboration, and advocate for continued efforts.

“Vaccines are one of the most influential innovations in human history, as they have the ability to prevent diseases that were once feared,” stated Dr. Tedros Adhanom Ghebreyesus, the Director-General of the World Health Organization (WHO). Vaccines have played a crucial role in eradicating smallpox and bringing polio to the verge of elimination. Furthermore, the development of vaccines against diseases such as malaria and cervical cancer has allowed us to make significant progress in combating these illnesses.

“Through ongoing research, investment, and collaboration, we have the potential to preserve millions of additional lives both presently and over the course of the next five decades.”

A novel mRNA vaccine candidate for highly malignant brain cancer has exhibited encouraging results in a limited-scale clinical trial, albeit with a unique approach. In addition to conducting vaccine trials on a small number of human cancer patients, the researchers are also utilizing data from 10 pet dogs.

It is customary for drugs and treatments intended for human use to undergo animal trials initially. Frequently, this phase of the process occurs subsequent to laboratory experiments conducted on cells but prior to any involvement of human volunteers in the administration of the drug. Despite ongoing endeavors to diminish animal testing and substitute it with alternative methods, it remains a fundamental component of pharmaceutical research.

Typically, however, our intention is not to medically treat animals for a disease they acquired in a natural manner. Scientists create models in species with organ systems that closely resemble those of humans, utilizing drugs, surgery, or genetic modification to imitate human diseases.

In the context of this mRNA vaccine, that stage was accomplished in mice. However, there was an additional, atypical measure. Dogs are the exclusive nonhuman species that are susceptible to the occurrence of spontaneous brain tumors. This makes them a valuable resource for testing treatments in a more authentic environment.

Ten pet dog owners granted consent for their canines to participate. Glioma, a type of cancer, is universally lethal, making this trial their sole available treatment option. In contrast to the typical average survival time of 30–60 days following a diagnosis, the dogs experienced a median survival of 139 days after receiving the vaccine, allowing for a significant increase in opportunities for treats and belly rubs.

Following successful outcomes in both the mice and the dogs, the researchers proceeded to administer the vaccine to four human patients diagnosed with glioblastoma. This is the most malignant type of brain cancer, characterized by a low rate of survival.

At present, it is premature to have a comprehensive understanding of the clinical impacts of the vaccine. However, it is established that all patients experienced either a prolonged period without illness or a longer-than-anticipated survival rate. The results are so encouraging that a larger Phase I trial is now scheduled to encompass both pediatric and adult populations.

What is the mechanism of action of the vaccine?

As observed in previous advancements in this field, one significant benefit of mRNA-based vaccines for cancer is their ability to be customized for individual patients. The glioblastoma vaccine incorporates this feature alongside a pioneering delivery system.

“Rather than injecting individual particles, we are injecting clusters of particles that are coiling around each other, similar to onions in a bag,” explained Dr. Elias Sayour, senior author from the University of Florida, in a statement. “The rationale behind this approach in the context of cancer is that these clusters stimulate the immune system to a greater extent than individual particles.”

Due to the COVID-19 pandemic, we have gained a greater understanding of mRNA vaccines; however, the mechanisms behind their functioning differ slightly. The RNA is obtained from the tumor cells of each patient and then enclosed in a lipid nanoparticle “costume.”. Upon reintroduction into the bloodstream, the immune system perceives this substance as a virus, thereby preparing itself to react to any remaining cancerous cells.

The process of personalization customizes the vaccine to suit the individual patient, thereby optimizing its effectiveness. Additionally, the delivery system enhances the immune system’s ability to respond quickly.

“Within a span of less than 48 hours, we may witness a transformation of these tumors from an ‘immune cold’ state, characterized by a scarcity of immune cells and a suppressed immune response, to an ‘immune hot’ state, marked by a highly active immune response,” Sayour noted.

“The study’s discovery that producing an mRNA cancer vaccine in this manner elicits comparable and robust reactions in mice, pet dogs with naturally occurring cancer, and human patients with brain cancer is a highly significant finding. This is because it is often uncertain how well the results of preclinical studies in animals will translate into similar responses in patients,” stated Dr. Duane Mitchell, a co-author of the study.

Sayour stated that the vaccine has the potential to be integrated with other immunotherapies as part of a combined treatment. “I am optimistic that this could represent a novel paradigm for patient treatment, a cutting-edge platform technology for modulating the immune system,” he stated.

The research findings have been published in the scientific journal Cell.