01 October 2021

Coronavirus Variants

Welcome back. Do you remember the old days, when COVID-19 wasn’t a threat? Oh, wait, that was only a few months ago.

With vaccine hesitancy, vaccine politicization, the my-freedom-trumps-public-health crowd and loads of misinformation, it’s difficult to keep the coronavirus controlled, especially when new variants keep popping up and spreading among the unvaccinated, unmasked and un-socially distanced.

Vaccination protesters (photo by John Lamparski-NurPhoto-AP from www.theatlantic.com/ideas/archive/2021/08/vaccine-refusers-hesitancy-mandates-fda-delta/619918/).
You’re familiar with all that, of course, but to keep terms straight, COVID-19, the coronavirus disease 2019, is caused by SARS-CoV-2, the severe acute respiratory syndrome coronavirus 2, which is part of a large family of coronaviruses. Multiple variants of SARS-CoV-2 have been documented. Variants arise because viruses constantly change through mutation.

OK, now that you’ve got all that, there’s a recent article I found of interest and thought you might too. The American Chemical Society, a nonprofit organization chartered by the U.S. Congress, has a weekly newsmagazine, Chemical & Engineering News (C&EN). C&EN interviewed scientists on how coronavirus variants are studied and judgements made as to how well they can be managed with existing vaccines. I’ll review highlights from the article.

Lab Testing
Researchers test new variants by comparing them with the current variants. The tests typically mix the virus with antibodies from the plasma of people who either recovered from COVID-19 or are fully vaccinated. (Plasma is the major liquid component of blood, consisting of water and dissolved constituents, including proteins. Antibodies are proteins that our immune system produces to fight the infection after infection or vaccination.)

Testing the ability of antibodies to block SARS-CoV-2 in Duke University’s Regional Biocontainment Lab (photo by Thomas Oguin III from cen.acs.org/biological-chemistry/infectious-disease/How-to-interpret-new-studies-coronavirus-variants/99/i32).
The primary test questions are (1) will the antibodies prevent the new variants from infecting our cells, and (2) how readily the new variants spread compared with their predecessors?

Although what happens in the lab isn’t necessarily what will happen in our bodies, the testing provides rapid, effective assessments of the variants.

Variant Infectiousness
Mutations can give new variants a tighter grip on our cells, such that a smaller amount of virus can start an infection. Other mutations may help the virus reproduce more quickly or in greater quantities, increasing the chance that an infected person will spread the virus.

A more infectious virus may not make people sicker, but it will infect more people, making outbreaks harder to control. A case in point is the Delta variant, which spreads more easily than the Beta variant, even though the Beta variant is better at evading our neutralizing antibodies.

Epidemiologists and modelers use population-level data to estimate how many people each infected person will infect. The original coronavirus was calculated to spread to 2 or 3 unvaccinated people who made no change in their behavior to prevent transmission. The Delta variant is calculated to spread to 6 or 7.

Reviewing Research on New Variants
I rarely blog about studies that haven’t been peer reviewed, and I sympathize with those keeping abreast of coronavirus research. The flow of new information is a deluge. Apparently, much of that information is shared on preprint servers before peer review. And apparently claims about new variants--claims that might reach the public--don’t always match the data.

The interviewed scientists approach these studies with care, ignoring claims and focusing on the testing, source of antibodies, how data on vaccine efficacy were collected, how mild or severe disease are defined, and if multiple variants were compared head-to-head or from different labs, where anything might differ.

Wrap Up
When fully vaccinated individuals become infected (“breakthrough infections”), those who are unvaccinated may wonder why get vaccinated. Why? Because the principal goal of vaccines is to prevent severe disease and death. Thus far, the vaccines have done well with less than 5% of fully vaccinated people hospitalized. As more infectious variants evolve, infections might increase.

Summary percentages of data on COVID breakthrough hospitalizations and deaths, New York Times, August 2021 (www.nytimes.com/interactive/2021/08/10/us/covid-breakthrough-infections-vaccines.html).

For healthy, fully vaccinated people, a mild infection with a variant could boost immunity. For immunocompromised people and older adults who normally don’t produce a lot of antibodies, booster shots could be important for improved protection.

But with so many people worldwide lacking a first shot and being potential sources of new variants, we have to question whether boosters should be distributed broadly before addressing the unvaccinated. Thanks for stopping by.

Center for Countering Digital Hate report on vaccine disinformation: www.counterhate.com/disinformationdozen
SARS-CoV-2 variants: www.cdc.gov/coronavirus/2019-ncov/variants/variant-info.html
Article on understanding coronavirus variants in C&EN: cen.acs.org/biological-chemistry/infectious-disease/How-to-interpret-new-studies-coronavirus-variants/99/i32
Summary of C&EN article on EurekAlert! website: www.eurekalert.org/news-releases/927837
Earlier C&EN article on SARS-CoV-2 variants: cen.acs.org/sections/new-covid-19-variants-vaccines-effective.html

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