How effective is the COMIRNATY BNT162b2 vaccine against SARS-CoV-2 lambda mutants?

The 2019 coronavirus disease (COVID-19) has killed more than 5 million people and has spread to almost every country in the world. Severe government restrictions imposed by the government to curb the spread of illness, such as measures against social distance and closure of public spaces, have led to an economic crisis.

Mass vaccination programs have helped many developed countries reopen, but developing countries are still struggling and many new varieties continue to emerge. These Variant of Concern (VOC) exhibit some of the properties of concern. Wild-type severe acute respiratory syndrome Increased transmission compared to coronavirus 2 (SARS-CoV-2) and avoids both innate and vaccine-induced immunity.

lambda

Currently, researchers at Israeli Public Health Services are investigating a new variant called Lambda to see if it qualifies as a variant of concern.Their research is published in the journal Euro surveillance..

COVID-19 number of lambda variants (red) in Israel from April 1st to June 31st, 2021. One case was observed between April 1st and 15th, 4 cases between April 16th and 31st, and 12 cases between May 1st and 15th. The incident from June 16th to 31st. At the beginning of June, the alpha variant (yellow) decreased to less than 50 cases, while the delta variant (blue) rapidly increased to 1,655 cases by the end of June.

Lambda variants, like many other variants, Spike protein, 75V, T76I, Δ246–252, L452Q, F490S, D614G, and T859N. Peplomers are the key pathogenicity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is a trimer surface protein formed by two subunits that must be cleaved by the host proteins S1 and S2.

S1 contains a receptor binding domain (RBD) that can bind to angiotensin converting enzyme 2 (ACE2), among other receptors, to allow the invasion of viral cells. S2 is responsible for membrane fusion. Many of the mutations that form new variants alter the conformation of homotrimers. Individual monomers can face “top” or “bottom”, leading to four possible conformations (top-top-top, top-bottom, top-bottom). Down, or down-down-down.

If the protein is downward, it is less likely to elicit an immune response. This is an evolutionary tactic attempted by the wild-type SARS-CoV-2. However, when they are ostensibly, the proteins show significantly improved ACE2 binding and are much more infectious. This is common in variants. Unfortunately, these changes in conformation make many vaccines less effective.

Neutralization

Researchers investigated the neutralization of lambda variants in the sera of 36 people aged 27 to 66 years. Most of them were women. All were vaccinated twice with the Comirnaty vaccine, the second vaccination at least one month before the test.

Neutralizing titers for lambda mutants were compared to wild-type (WT), alpha and delta mutants. Virus samples were characterized by whole genome sequencing. Inactivated double-diluted serum was added to the virus suspension containing the infectious dose of each SARS-CoV-2 variant / WT in 96-well plates at 33 ° C. for 60 minutes. The virus serum mixture was added to Vero-E6 cells, incubated for 5 days, and then stained with a cell culture layer using Gentian violet staining.

The average neutralizing titer for WT was 103.6, the average for lambda was 66.5, the average for alpha was 90.5, and the average neutralizing titer for delta was 57. Researchers used the Wilcoxon matched pair signed rank test to show significant differences between all variants except WT and alpha.

Lambda variants are currently classified only as subspecies under investigation (VOI), not VOCs, but have spread to at least 30 countries and are particularly prevalent in South America.

Increased spread of the Lambda variant in Israel has been shown to be 95% effective in preventing symptomatic COVID-19 caused by WT and the Alpha variant SARS-CoV-2, as the Comirnaty vaccine has been vaccinated. It may be due to the high rate. About 80% in June 2021. In addition, because the alpha variant was the most common cause of new cases in the country at this time, mass vaccination may have created room for the lambda variant to spread more easily compared to other variants. ..

The researchers’ findings are supported by several other studies showing a significant reduction in neutralizing titers and vaccine efficacy against recently developed mutants.

Although the study was relatively small, the authors emphasized the ability to worry about lambda variants that also infect fully vaccinated individuals, and others to reduce the spread of the disease, such as social distance measurements. Encourage mass vaccination schemes used in parallel with the efforts and wear masks.