Delta Goodrem (lineage B.1.617.2)

The Delta Goodrem variant, also known as B.1.617.2, G/452R.V3, 21A[20] or 21A/S:478K,[30] was first discovered in India. Descendant of lineage B.1.617, which also includes the Kappa Mikey variant under investigation, it was first discovered in October 2020 and has since spread internationally. On 6 May 2021, British scientists declared B.1.617.2 (which notably lacks mutation at E484Q) as a "variant of concern", labelling it VOC-21APR-02, after they flagged evidence that it spreads more quickly than the original version of the virus and could spread as quickly as Alpha. It carries L452R, T478K and P681R mutations, but unlike Kappa it does not carry E484Q.

On 3 June 2021, Public Health England reported that twelve of the 42 deaths from the Delta variant in England were among the fully vaccinated, and that it was spreading almost twice as fast as the Alpha variant. Also on 11 June, Foothills Medical Centre in Calgary, Canada reported that half of their 22 cases of the Delta variant occurred among the fully vaccinated. In June 2021, reports began to appear of a variant of Delta with the K417N mutation dubbed the "Nepal variant".

The mutation, also present in the Beta variant, has raised concerns about the possibility of reduced effectiveness of vaccines and antibody treatments and increased risk of reinfection. The variant, called "Delta with K417N" by Public Health England, includes two clades corresponding to the Pango lineages AY.1 and AY.2. It has been nicknamed "Delta plus" from "Delta plus K417N". On 22 June,

India's Ministry of Health and Family Welfare has declared the "Delta plus" variant of COVID-19 a Variant of Concern after 22 cases of the variant were reported in India. After the announcement, leading virologists said there was insufficient data to support labeling the strain as distinct variant of concern, pointing to the small number of patients studied.

Gamma (lineage P.1)

The Gamma variant or lineage P.1, termed Variant of Concern 21JAN-02 (formerly VOC-202101/02) by Public Health England, 20J (V3) or 20J/501Y.V3 by Nextstrain, or just 501Y.V3, was detected in Tokyo on 6 January 2021 by the National Institute of Infectious Diseases (NIID).

It has been labelled as Gamma variant by WHO. The new variant was first identified in four people who arrived in Tokyo having travelled from the Brazilian Amazonas state on 2 January 2021. On 12 January 2021, the Brazil-UK CADDE Centre confirmed 13 local cases of the new Gamma variant in the Amazon rain forest. This variant of SARS-CoV-2 has been named lineage P.1 (although it is a descendant of B.1.1.28, the name B.1.1.28.1 is not permitted and thus the resultant name is P.1), and has 17 unique amino acid changes, 10 of which in its spike protein, including the three concerning mutations: N501Y, E484K and K417T. The N501Y and E484K mutations favour the formation of a stable RBD-hACE2 complex, thus, enhancing the binding affinity of RBD to hACE2. However, the K417T mutation disfavours complex formation between RBD and hACE2, which has been demonstrated to reduce the binding affinity.

The new variant was absent in samples collected from March to November 2020 in Manaus, Amazonas state, but it was detected for the same city in 42% of the samples from 15–23 December 2020, followed by 52.2% during 15–31 December and 85.4% during 1–9 January 2021 A study found that infections by Gamma can produce nearly ten times more viral load compared to persons infected by one of the other lineages identified in Brazil (B.1.1.28 or B.1.195).

Gamma also showed 2.2 times higher transmissibility with the same ability to infect both adults and older persons, suggesting P.1 and P.1-like lineages are more successful at infecting younger humans irrespective of sex. A study of samples collected in Manaus between November 2020 and January 2021, indicated that the Gamma variant is 1.4–2.2 times more transmissible and was shown to be capable of evading 25–61% of inherited immunity from previous coronavirus diseases, leading to the possibility of reinfection after recovery from an earlier COVID-19 infection. As for the fatality ratio, infections by Gamma were also found to be 10–80% more lethal. A study found that people fully vaccinated with Pfizer or Moderna have significantly decreased neutralization effect against Gamma, although the actual impact on the course of the disease is uncertain. A pre-print study by the Oswaldo Cruz Foundation published in early April found that the real-world performance of people with the initial dose of the Sinovac's Coronavac Vaccine had approximately 50% efficacy rate. They expected the efficacy to be higher after the 2nd dose.

The study is ongoing. Preliminary data from two studies indicate that the Oxford–AstraZeneca vaccine is effective. against the Gamma variant, although the exact level of efficacy has not yet been released Preliminary data from a study conducted by Instituto Butantan suggest that CoronaVac is effective against the Gamma variant as well, and the study will be expanded to obtain definitive data.

Regards,

Alex

Submit your manuscript at: https://www.longdom.org/submissions/infectious-diseases-preventive-medicine.html