All COVID-19 variants show some resistance to vaccine-induced antibodies, but boosters can temporarily help, says a study in the journal Vaccine.“Our data reflect the poor durability of vaccine-induced nAb (neutralizing antibody) responses,” wrote the study’s authors from Louisiana State University. The body makes neutralizing antibodies to prevent a virus from infecting cells.For the study entitled Dynamics of Serum-Neutralizing Antibody Responses in Vaccinees through Multiple Doses of the BNT162b2 Vaccine, antibodies were collected from sixteen recipients of two primary shots of COVID-19 vaccines and a booster who had never been infected. They were followed over 420 days and had their antibodies to COVID-19 viruses tested at weekly and monthly intervals. Participants were given three doses of the Pfizer COVID-19 mRNA vaccine for the original Wuhan variant.Antibodies collected three weeks after the second and third doses had strong neutralizing effects against the original COVID-19 variant, but these neutralizing antibodies rapidly declined. Four months after the second dose and six months after the third, neutralizing antibody levels had fallen back to pre-vaccination levels.Other variants were significantly resistant to antibodies formed after the second and third shots, even three weeks after vaccination, when the effects of the antibodies are considered the strongest. That meant these shots were less effective at preventing symptomatic infections from subsequent variants, especially omicron.IgG4 and IgG2 antibodies increased significantly after the third dose, whereas they had previously been quite minimal. A rise in IgG4 levels has also been reported in other studies to suggest potential immune tolerance.Immune tolerance occurs when the immune system becomes unresponsive to an antigen or a particle that is causing disease. In this study, this particle was the spike protein the body makes upon exposure to mRNA vaccines. As a receptor-binding domain (RBD), the protein docks with a cell to gain entrance.“The dynamics of immune escape by RNA viruses limits the efficacy of vaccine-induced protective immune responses. In particular, mutations within the spike RBD afford viral resistance against neutralizing activities of both therapeutic antibodies and immune sera,” the authors wrote. In a review published on December 26 2023, in Vaccine, researchers found that non-live vaccines such as influenza, COVID-19, hepatitis B, and diphtheria-tetanus-pertussis (DTaP) tend to cause adverse nonspecific effects, increasing a person’s risks of all-cause mortality and infections from other diseases. The study was led by biologist Alberto Rubillo-Casillas from Autlán Regional Hospital in Mexico.Non-live vaccines use inactivated viruses, fragments or genes of the pathogen to trigger an immune response without pathogen replication.Live vaccines prompt a much stronger immune defence, typically requiring only one shot, while the weaker response of non-live vaccines often necessitate multiple shots.The oral live polio vaccine, the Bacillus Calmette-Guérin (BCG) vaccine for tuberculosis and smallpox vaccines were found to have beneficial NSEs.“Live vaccines ... elicit epigenetic alterations that train the innate immune system and increase immunity to unrelated infections. In opposition, non‐live vaccines may promote ‘tolerance’ that increases susceptibility to unrelated illnesses,” the study said.The study leaned heavily on the work of Dr. Christine Stabell Benn. In a pre-pandemic TED talk, Benn compared real infections to a competitive tennis match and live vaccines to a tennis coach. The tennis coach trains the body to have “a wide variety of tricks” against the pathogen. However, Benn compared non-live vaccines to tennis ball machines that shoot out balls at a specific speed and spot.“So you may be ill-prepared and even worse off when a real opponent enters the court, and the balls start coming and hitting elsewhere than what you trained for,” Benn said.
