In a recent study conducted at the Baylor College of Medicine, Houston, USA, scientists have identified six vaccine breakthrough cases caused by the delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
A vaccine breakthrough case is defined as the detection of SARS-CoV-2 infection in individuals who are fully vaccinated against coronavirus disease 2019 (COVID-19). The study is currently available on the medRxiv* preprint server.
Background
Recently, India has seen a significant rise in new COVID-19 cases predominantly caused by the delta variant (B.1.617.2) of SARS-CoV-2. Similar to the alpha (B.1.1.7), beta (B.1.351), and gamma (P.1) variants, the delta variant has gained beneficial mutations in the spike protein, which make it more infectious and pathogenic than previously circulating variants.
The delta variant belongs to the B.1.617 lineage that is currently circulating in more than 50 countries. Because of its significant threat to public health, the delta variant has been designated as the Variant of Concern (VOC) by the World Health Organization.
Studies investigating vaccine efficacy against emerging SARS-CoV-2 variants have indicated that the delta variant is partially resistant to vaccine-induced antibodies. A study conducted in the UK has indicated that the Pfizer/BioNTech COVID-19 vaccines is 88% effective in preventing symptomatic disease caused by the delta variant.
In the current study, the scientists have described the transmission of delta variants among family members who were attending a wedding ceremony with 92 guests. The wedding events were held outside in a large open-air tent, and all guests were fully vaccinated.
Important observations
The scientists identified a total of six individuals at the wedding ceremony who tested positive for SARS-CoV-2 and were symptomatic. Of them, one developed severe COVID-19 requiring monoclonal antibody infusion and one died eventually. Based on encounter timings and viral sequence similarities, the scientists suggested that two persons traveling from India probably have transmitted the delta variant to other guests during the wedding events.
Soon after developing symptoms including fatigue, cough, and fever, both guests from India tested positive for SARS-CoV-2 infection. At day 6 post-wedding, the man without comorbidity was admitted to a hospital because of worsening symptoms. One month after the wedding, he died due to COVID-19 related complications.
Four other guests who also tested positive for SARS-CoV-2 had confirmed interactions with the guests from India. Of 4 guests who were fully immunized with the Pfizer/BioNTech or Moderna COVID-19 vaccine, one developed severe COVID-19 that required infusion of monoclonal antibodies.
Testing of viral variant
Nasopharyngeal swab samples were collected from all six guests and analyzed by reverse transcription-polymerase chain reaction (RT-PCR) to detect viral variants. All samples tested positive for the original Wuhan strain of SARS-CoV-2 and negative for the alpha variant. All positive samples were subsequently sequenced by Swift Normalase Amplicon Panels with multiple overlapping amplicons to identify the causative variant. The findings revealed that all six guests were infected with the delta variant of SARS-CoV-2 (B.1.617.2).
News
How the FDA opens the door to risky chemicals in America’s food supply
Lining the shelves of American supermarkets are food products with chemicals linked to health concerns. To a great extent, the FDA allows food companies to determine for themselves whether their ingredients and additives are [...]
Superbug crisis could get worse, killing nearly 40 million people by 2050
The number of lives lost around the world due to infections that are resistant to the medications intended to treat them could increase nearly 70% by 2050, a new study projects, further showing the [...]
How Can Nanomaterials Be Programmed for Different Applications?
Nanomaterials are no longer just small—they are becoming smart. Across fields like medicine, electronics, energy, and materials science, researchers are now programming nanomaterials to behave in intentional, responsive ways. These advanced materials are designed [...]
Microplastics Are Invading Our Arteries, and It Could Be Increasing Your Risk of Stroke
Higher levels of micronanoplastics were found in carotid artery plaque, especially in people with stroke symptoms, suggesting a potential new risk factor. People with plaque buildup in the arteries of their neck have been [...]
Gene-editing therapy shows early success in fighting advanced gastrointestinal cancers
Researchers at the University of Minnesota have completed a first-in-human clinical trial testing a CRISPR/Cas9 gene-editing technique to help the immune system fight advanced gastrointestinal (GI) cancers. The results, recently published in The Lancet Oncology, show encouraging [...]
Engineered extracellular vesicles facilitate delivery of advanced medicines
Graphic abstract of the development of VEDIC and VFIC systems for high efficiency intracellular protein delivery in vitro and in vivo. Credit: Nature Communications (2025). DOI: 10.1038/s41467-025-59377-y. https://www.nature.com/articles/s41467-025-59377-y Researchers at Karolinska Institutet have developed a technique [...]
Brain-computer interface allows paralyzed users to customize their sense of touch
University of Pittsburgh School of Medicine scientists are one step closer to developing a brain-computer interface, or BCI, that allows people with tetraplegia to restore their lost sense of touch. While exploring a digitally [...]
Scientists Flip a Gut Virus “Kill Switch” – Expose a Hidden Threat in Antibiotic Treatment
Scientists have long known that bacteriophages, viruses that infect bacteria, live in our gut, but exactly what they do has remained elusive. Researchers developed a clever mouse model that can temporarily eliminate these phages [...]
Enhanced Antibacterial Polylactic Acid-Curcumin Nanofibers for Wound Dressing
Background Wound healing is a complex physiological process that can be compromised by infection and impaired tissue regeneration. Conventional dressings, typically made from natural fibers such as cotton or linen, offer limited functionality. Nanofiber [...]
Global Nanomaterial Regulation: A Country-by-Country Comparison
Nanomaterials are materials with at least one dimension smaller than 100 nanometres (about 100,000 times thinner than a human hair). Because of their tiny size, they have unique properties that can be useful in [...]
Pandemic Potential: Scientists Discover 3 Hotspots of Deadly Emerging Disease in the US
Virginia Tech researchers discovered six new rodent carriers of hantavirus and identified U.S. hotspots, highlighting the virus’s adaptability and the impact of climate and ecology on its spread. Hantavirus recently drew public attention following reports [...]
Studies detail high rates of long COVID among healthcare, dental workers
Researchers have estimated approximately 8% of Americas have ever experienced long COVID, or lasting symptoms, following an acute COVID-19 infection. Now two recent international studies suggest that the percentage is much higher among healthcare workers [...]
Melting Arctic Ice May Unleash Ancient Deadly Diseases, Scientists Warn
Melting Arctic ice increases human and animal interactions, raising the risk of infectious disease spread. Researchers urge early intervention and surveillance. Climate change is opening new pathways for the spread of infectious diseases such [...]
Scientists May Have Found a Secret Weapon To Stop Pancreatic Cancer Before It Starts
Researchers at Cold Spring Harbor Laboratory have found that blocking the FGFR2 and EGFR genes can stop early-stage pancreatic cancer from progressing, offering a promising path toward prevention. Pancreatic cancer is expected to become [...]
Breakthrough Drug Restores Vision: Researchers Successfully Reverse Retinal Damage
Blocking the PROX1 protein allowed KAIST researchers to regenerate damaged retinas and restore vision in mice. Vision is one of the most important human senses, yet more than 300 million people around the world are at [...]
Differentiating cancerous and healthy cells through motion analysis
Researchers from Tokyo Metropolitan University have found that the motion of unlabeled cells can be used to tell whether they are cancerous or healthy. They observed malignant fibrosarcoma [...]
