Scientists claim that the Delta variant has a greater ability to escape immunity in recovered patients
This was warned by researchers from Columbia University, who, using a computer model, also estimated the transmission power of the other variants
The different variants of SARS-CoV-2 have so far successfully tested the efficacy of vaccines against COVID-19. And in line with the concern that aroused in the scientific community since its appearance, it is now known that the Delta variant, first identified in India in December 2020, is more contagious than the original SARS-CoV-2 and is better able to escape previous or natural immunity, present in recovered patients, that is, they have already been infected with the virus in their lineage that emerged in Wuhan.
As estimated by researchers from Columbia University’s Mailman School of Public Health using a computer model, the mutation that emerged in India is about 60% more contagious than the original coronavirus from Wuhan. You can also escape immunity from a previous infection almost half the time, the same researchers noted.Compared to Delta, Beta and Gamma are less transmissible but better able to escape immunity. Compared to the original virus, the Iota variant is more fatal to older adults.
Findings from three SARS-CoV-2 variant studies were published on the medRxiv preprint server prior to publication in a peer-reviewed journal.
Wan Yang, PhD, assistant professor of epidemiology and lead author of the studies noted that“New variants of SARS-CoV-2 have become widespread, but currently vaccines are still very effective in preventing serious illnesses caused by these infections, so get vaccinated if you haven’t.”
“It is important that we closely monitor the spread of these variants to guide ongoing preventive measures, vaccination campaigns, and evaluation of vaccine efficacythe expert analyzed. More fundamentally, to limit the emergence of new variants and end the COVID-19 pandemic, we need global efforts to vaccinate all populations around the world and continue to use other public health measures until a sufficient portion of the population is protected by vaccination ”.
In the researchers’ appreciation, the Delta variant (B.1.617.2) is 10-20% more transmissible than the Alpha, another highly contagious variant of concern. Furthermore, unlike Alpha, which was shown to cause minimal immune evasion, Delta can also evade previous immunity in about half of the individuals previously infected by the ancestral strain.
These findings are in line with UK estimates that Alpha is around 1.5 times more likely to result in infection (combining a 10-20% increase in transmissibility with a <~ 50% increase in susceptibility due to immune evasion by a previous natural infection and, to a lesser extent, vaccination).
Compared to Beta and Gamma, the Delta variant is more transmissible but less able to escape immunity. The decline in Delta cases in India in early May is likely due to the implementation of public health measures and weather conditions. The monsoon season (June-September) and winter (December-January) could see increased transmission of the virus. The Delta variant was first detected in December 2020 and spread to 142 countries, as of August 10.
The researchers developed computer models of COVID-19 to estimate changes in transmissibility and immune escape for each variant, based on case and mortality data from the country where each variant arose. The models took into account underdetection of infection, disease seasonality, concurrent non-pharmaceutical interventions, and mass vaccination.
“New variants of SARS-CoV-2 such as B.1.526 could increase transmissibility, evade previous immunity and increase the severity of the disease. Early preparation and close monitoring of SARS-CoV-2 variants and their epidemiological characteristics are crucial to the response to the COVID-19 pandemic, as it continues to pose a global public health threat.”, They concluded.