Antibody-dependent enhancement (ADE), also known as vaccine-enhanced disease, occurs when certain antibodies produced by a vaccine don’t protect an individual from infection but enhances viral entrance, making the disease worse.
“Cases in places that are heavily vaccinated, cases go up but deaths don’t go up nearly as much as they would have last year in an unvaccinated population,” Bhattacharya said. “That’s evidence against any macro-level impact of antibody-dependent enhancement.”
“You would have expected that death would actually go up relative to what it was last year if ADE was a really important phenomenon in the data. But that’s not what I’m currently seeing.”
Instead, Bhattacharya says the data seems to suggest that there is a decoupling of cases and deaths, where although cases are rising, the fatality rate is not and may be declining.
“You would have expected that death would actually go up relative to what it was last year if ADE was a really important phenomenon in the data but that’s not what I’m seeing,” Bhattacharya said. “I’m seeing instead a decoupling of cases and deaths in the UK is dramatic, Iceland, dramatic, [and] Sweden.”
The researchers used molecular modeling to show that certain antibodies that do not neutralize the CCP virus had a “higher affinity for Delta variants” than the original virus strain that first emerged in Wuhan, China.
“However, in the case of the Delta variant, neutralizing antibodies have a decreased affinity for the spike protein, whereas facilitating antibodies display a strikingly increased affinity,” the authors wrote. “Thus, ADE may be a concern for people receiving vaccines based on the original Wuhan strain spike sequence (either mRNA or viral vectors).”
Although the modeling raised concerns about ADE, the researchers said that the rare phenomenon has not been observed with mass vaccination. However, they said that ADE should be further investigated with the delta variant.
Countries with high vaccination rates are seeing a surge in COVID-19 cases, even in severe disease and hospitalization.
Scientists say the reason for the surge in breakthrough cases may possibly result from waning vaccine effectiveness and the ability of the delta variant to evade the vaccine.
Mutation on Spike Protein Possible Reason for Decrease in Vaccine Effectiveness
Studies have shown that antibodies bind to three areas on the spike protein: the N-terminal domain, the receptor-binding domain, and the S2 subunit. The N-terminal and receptor-binding domains make up the S1 subunit, which binds to the receptor of the human cell, whereas the S2 subunit fuses the membranes of the virus and the host cell.
They also found that the N-terminal domain had “mutated frequently, especially in several emerging variants of concern.”
Prior to the findings, many studies concentrated on the receptor-binding domain of the spike protein because it attaches directly to human cells to allow the virus to infect them. Thus, the receptor-binding domain became the prime target of antibodies generated by COVID-19 vaccines and other therapeutics.
Mass Vaccination Concerns
Some experts have raised concerns about the ongoing mass vaccinations during a pandemic. Nobel Laureate Luc Montagnier who co-discovered the human immunodeficiency virus (HIV) claimed in May that vaccinations were creating the emerging variants.
The vaccine expert explained that the vaccines create antibodies that force the virus to either die or find another way to survive by mutating.
Montagnier said he is closely following the situation and conducting a study of patients who got re-infected with COVID-19 after being vaccinated, adding that he will show that vaccinations “are creating the variants that are resistant to the vaccine.”
“There is no evidence the vaccines are creating more variants,” the author wrote. “In fact, most human vaccines have not been undermined by microbial evolution.”
“Variants of the SARS-CoV-2 virus are created at random, through the mass spread of the virus. Vaccination is part of the solution for suppressing transmissions,” the author added.
Studies have shown that the COVID-19 vaccines do not stop infection or transmission of the virus, particularly with the delta variant.
Bhattacharya said that not everyone should get vaccinated, especially children who are at low risk for COVID-19. Whereas, children are at higher risk for flu, even during the pandemic.
“Last year, more children died of the flu even though the flu disappeared and we had a vaccine for the flu last year, and more children died of the flu than COVID. The same is true this year,” said Bhattacharya.
Instead, he said “the right way to use the vaccine” is in focused protection.
“Use it to protect the vulnerable because otherwise, they face a high risk of COVID. For the rest of the population, don’t force people to take it,” Bhattacharya said.