Daijiworld Media Network - Ontario

Ontario, Nov 10: A newly identified COVID-19 variant, PJ.2.1, is attracting attention as it spreads across North America, Europe, Australia, New Zealand and parts of Asia, raising questions about its potential to trigger another wave of infections and the protection offered by existing immunity.

First detected in Ontario, Canada, in May 2026, PJ.2.1 is a lineage of SARS-CoV-2, the virus responsible for COVID-19. Researchers describe it as a 'saltation variant', meaning it emerged with a relatively large number of genetic changes rather than accumulating mutations gradually.

According to research published by Markus Hoffmann and colleagues in the Journal of Infection in October 2026, PJ.2.1 originated from MC.10.1.7, a descendant of the JN.1 lineage that circulated until May 2025.

The first documented sample was identified in Ontario on May 2, 2026. Subsequent detections were reported in Alberta, British Columbia and New Brunswick in Canada. The United States recorded its first case in New York City on June 30, followed by detections in several other states, including California, Arizona, New Jersey, Virginia, North Carolina, Missouri, Oklahoma, Colorado and Florida.

International detections have also been reported in Singapore, Australia, New Zealand, Israel, France and Spain. Researchers in Spain identified evidence of local transmission chains across multiple regions.

Public Health Ontario's genomic surveillance report indicates that PJ.2.1 accounted for 25.2 per cent of sequenced SARS-CoV-2 samples between September 20 and October 17, up from 16.9 per cent during the preceding four-week period.

One of the key findings of recent research is that PJ.2.1 has a highly mutated spike protein, which helps the virus enter human cells. Laboratory experiments suggest that the variant may interact more efficiently with ACE2, a receptor found on the surface of human cells.

SARS-CoV-2 uses its spike protein to attach to ACE2 receptors and enter cells. Changes in the spike protein can influence how effectively the virus binds to these receptors, potentially affecting its ability to infect cells.

Researchers found that PJ.2.1 was less susceptible to inhibition by an antibody targeting ACE2 than the other variants examined, suggesting that its spike protein may bind more effectively to the receptor.

However, the findings did not indicate substantially greater immune evasion compared with most of the other variants tested. Antibodies from people who had received an LP.8.1-adapted COVID-19 vaccine were able to neutralise PJ.2.1. Its sensitivity to neutralisation was only 1.8 times lower than that of the LP.8.1 reference variant.

The findings suggest that increased ACE2 binding, rather than significantly enhanced ability to evade antibodies, could be contributing to the variant's spread. However, the experiments were conducted in laboratory models and do not establish how efficiently PJ.2.1 spreads between people or whether it causes more severe illness in real-world conditions.

There is currently no established symptom profile unique to PJ.2.1. COVID-19 symptoms can resemble those of seasonal influenza, the common cold and other respiratory infections.

Common symptoms include fever or chills, cough, sore throat, runny or blocked nose, headache, muscle and body aches, fatigue and weakness. Some people may also experience shortness of breath, gastrointestinal problems or changes in their sense of smell and taste.

The World Health Organization (WHO) has cautioned that COVID-19 and influenza can produce overlapping symptoms, making it difficult to distinguish between the infections based on symptoms alone.

This is particularly important during periods when several respiratory viruses are circulating. People experiencing fever, sore throat or persistent fatigue should not automatically assume that they have a common cold or influenza. Diagnostic testing can help establish whether an infection is caused by SARS-CoV-2 or another respiratory virus, while genomic sequencing helps public health laboratories identify specific viral lineages.

At present, there is insufficient clinical evidence to conclude that PJ.2.1 causes more severe COVID-19 or increases the risk of hospitalisation and death. The research published in the Journal of Infection primarily examined the variant's genetic characteristics, cell entry and susceptibility to antibodies. It did not establish an increase in disease severity among infected patients.

The distinction between transmissibility, immune escape and disease severity is important. A variant may spread more rapidly without necessarily causing more serious illness.

Researchers also noted that PJ.2.1 was detected more frequently among older age groups, particularly people aged 70 and above. However, this observation does not establish that the variant specifically targets older people or causes more severe disease in them.

Older adults, people with weakened immune systems and those with underlying conditions such as diabetes, heart disease and chronic respiratory illnesses remain at greater risk of severe COVID-19 complications.

The emergence of PJ.2.1 calls for continued genomic surveillance and appropriate respiratory infection precautions rather than panic. The WHO's variant-tracking framework monitors emerging lineages based on their genetic characteristics and potential public health implications. PJ.2.1 was not included among the variants of interest or variants under monitoring listed in the WHO's July 2026 update.

COVID-19 vaccination continues to be an important measure for reducing the risk of severe illness, hospitalisation and death. Although laboratory findings involving vaccine-induced antibodies are encouraging, they do not establish how effective vaccination is against PJ.2.1 infection under real-world conditions. People at higher risk should consult healthcare providers about recommended vaccinations and booster doses.

In India, the Indian SARS-CoV-2 Genomics Consortium (INSACOG) provides a framework for monitoring genetic changes in circulating coronavirus strains through genomic sequencing. However, the available data do not establish whether PJ.2.1 has been detected in the country.

The emergence of PJ.2.1 highlights how SARS-CoV-2 continues to evolve years after the COVID-19 pandemic. While its growing presence across several countries warrants attention, current research does not establish that it causes more severe illness or significantly escapes vaccine-induced immunity. Continued genomic surveillance, appropriate testing and vaccination of vulnerable populations remain important in managing the ongoing risk of COVID-19.