- Research has found a significant fall in levels of antibodies against SARS-CoV-2, the virus that causes COVID-19, 6 months after the second dose of the Pfizer-BioNTech vaccine.
- Clinical evidence also suggests that the risk of getting a “breakthrough” infection gradually increases in the months after vaccination.
- Despite declines in antibody levels, other branches of the adaptive immune system appear to provide strong protection against severe infection and death.
- However, booster shots could protect the most vulnerable individuals, reduce transmission, and help suppress the emergence of new strains.
In the United States, the Food and Drug Administration (FDA)Trusted Source has approved third doses, or “boosters,” of the Pfizer-BioNTech COVID-19 vaccine for people over the age of 65 years.
It also approved boosters for people with health conditions that put them at risk of severe COVID-19 and for people whose jobs expose them to a high risk of infection, including healthcare workers and teachers.
The agency had already givenTrusted Source the green light to boosters for individuals with severely weakened immune systems, such as organ transplant patients.
But is there any evidence to justify a more widespread rollout of booster shots in the general population?
A recent study found that serum levels of antibodies against the spike protein of the virus, which it uses to gain entry to cells, start to wane around 12 weeks after the second dose of the Pfizer vaccine.
The researchers discovered that by 6 months after the second dose, median levels of these antibodies had fallen to around 7% of their peak level, with a range of 2–25%. The researchers say that this decline is expected.
Other workTrusted Source has shown that after having an mRNA-based vaccine against SARS-CoV-2, antibodies may not be circulating, but they are at peak activity within the lymph nodes by 12 weeks.
Cells that remember
At first glance, this appears to represent a worrying loss of immunity, but antibodies are only one branch of the body’s adaptive immune system.
The adaptive immune system also includes cells that remember past infections or vaccinations and swing into action if they encounter the same infectious agent again.
A recent preprint of a study reports that the number of immune cells known as memory B cells that recognize the virus actually increases 3–6 months after the second dose of the Pfizer or Moderna vaccine.
Remarkably, even though these vaccines use genetic material from the original variant of the virus, the B cells also recognized the Alpha, Beta, and Delta variants.
This is because the precursors of these B cells evolve over time in the body through a process of random mutation, which allows the mature cells to detect new variants of the virus as they arise.
The research also found two other types of immune cell primed to detect the virus in most individuals 6 months after their second dose of vaccine.
Known as helper T cells (CD4+ cells) and killer T cells (CD8+ cells), these help ramp up the immune response and destroy infected cells, respectively…
News
Platelet-inspired nanoparticles could improve treatment of inflammatory diseases
Scientists have developed platelet-inspired nanoparticles that deliver anti-inflammatory drugs directly to brain-computer interface implants, doubling their effectiveness. Scientists have found a way to improve the performance of brain-computer interface (BCI) electrodes by delivering anti-inflammatory drugs directly [...]
After 150 years, a new chapter in cancer therapy is finally beginning
For decades, researchers have been looking for ways to destroy cancer cells in a targeted manner without further weakening the body. But for many patients whose immune system is severely impaired by chemotherapy or radiation, [...]
Older chemical libraries show promise for fighting resistant strains of COVID-19 virus
SARS‑CoV‑2, the virus that causes COVID-19, continues to mutate, with some newer strains becoming less responsive to current antiviral treatments like Paxlovid. Now, University of California San Diego scientists and an international team of [...]
Lower doses of immunotherapy for skin cancer give better results, study suggests
According to a new study, lower doses of approved immunotherapy for malignant melanoma can give better results against tumors, while reducing side effects. This is reported by researchers at Karolinska Institutet in the Journal of the National [...]
Researchers highlight five pathways through which microplastics can harm the brain
Microplastics could be fueling neurodegenerative diseases like Alzheimer's and Parkinson's, with a new study highlighting five ways microplastics can trigger inflammation and damage in the brain. More than 57 million people live with dementia, [...]
Tiny Metal Nanodots Obliterate Cancer Cells While Largely Sparing Healthy Tissue
Scientists have developed tiny metal-oxide particles that push cancer cells past their stress limits while sparing healthy tissue. An international team led by RMIT University has developed tiny particles called nanodots, crafted from a metallic compound, [...]
Gold Nanoclusters Could Supercharge Quantum Computers
Researchers found that gold “super atoms” can behave like the atoms in top-tier quantum systems—only far easier to scale. These tiny clusters can be customized at the molecular level, offering a powerful, tunable foundation [...]
A single shot of HPV vaccine may be enough to fight cervical cancer, study finds
WASHINGTON -- A single HPV vaccination appears just as effective as two doses at preventing the viral infection that causes cervical cancer, researchers reported Wednesday. HPV, or human papillomavirus, is very common and spread [...]
New technique overcomes technological barrier in 3D brain imaging
Scientists at the Swiss Light Source SLS have succeeded in mapping a piece of brain tissue in 3D at unprecedented resolution using X-rays, non-destructively. The breakthrough overcomes a long-standing technological barrier that had limited [...]
Scientists Uncover Hidden Blood Pattern in Long COVID
Researchers found persistent microclot and NET structures in Long COVID blood that may explain long-lasting symptoms. Researchers examining Long COVID have identified a structural connection between circulating microclots and neutrophil extracellular traps (NETs). The [...]
This Cellular Trick Helps Cancer Spread, but Could Also Stop It
Groups of normal cbiells can sense far into their surroundings, helping explain cancer cell migration. Understanding this ability could lead to new ways to limit tumor spread. The tale of the princess and the [...]
New mRNA therapy targets drug-resistant pneumonia
Bacteria that multiply on surfaces are a major headache in health care when they gain a foothold on, for example, implants or in catheters. Researchers at Chalmers University of Technology in Sweden have found [...]
Current Heart Health Guidelines Are Failing To Catch a Deadly Genetic Killer
New research reveals that standard screening misses most people with a common inherited cholesterol disorder. A Mayo Clinic study reports that current genetic screening guidelines overlook most people who have familial hypercholesterolemia, an inherited disorder that [...]
Scientists Identify the Evolutionary “Purpose” of Consciousness
Summary: Researchers at Ruhr University Bochum explore why consciousness evolved and why different species developed it in distinct ways. By comparing humans with birds, they show that complex awareness may arise through different neural architectures yet [...]
Novel mRNA therapy curbs antibiotic-resistant infections in preclinical lung models
Researchers at the Icahn School of Medicine at Mount Sinai and collaborators have reported early success with a novel mRNA-based therapy designed to combat antibiotic-resistant bacteria. The findings, published in Nature Biotechnology, show that in [...]
New skin-permeable polymer delivers insulin without needles
A breakthrough zwitterionic polymer slips through the skin’s toughest barriers, carrying insulin deep into tissue and normalizing blood sugar, offering patients a painless alternative to daily injections. A recent study published in the journal Nature examines [...]
