Scientists around the world have been racing to learn more about the new omicron strain of SARS-CoV-2, first declared a “variant of concern” on Nov. 26, 2021 by the World Health Organization. Officials cautioned that it would take several weeks before they’d know whether the recently emerged coronavirus variant is more contagious and causes more or less serious COVID-19 than delta and other earlier variants, and whether current vaccines can ward it off.

Peter Kasson is a virologist and biophysicist at the University of Virginia who studies how viruses such as SARS-CoV-2 enter cells and what can be done to stop them. Here he explains what lab-based scientists are doing to help answer the outstanding questions about omicron.

Does prior immunity protect against omicron?

These are the key lab results everyone is waiting for: How effective are the antibodies people already have at fighting off omicron? If you got the booster shot, are you protected? Or if you had COVID-19 and then were vaccinated?

The goal is to see how well antibodies from real people who have had COVID-19 or have been vaccinated against it can hold off omicron in petri dishes in the lab. Scientists expect that antibodies from people exposed to other variants won’t work as well against omicron because of its mutations, but they need to measure how much less well and whether it’s still enough to stop the virus.

To answer these questions, most researchers first make a version of the SARS-CoV-2 virus that can enter cells but not reproduce. A few specialized labs with extra levels of biosecurity use the actual virus. Scientists add antibodies from the blood of people vaccinated against or recovered from COVID-19 to the virus. They then mix this with human lung cells to see whether the antibodies can stop the virus from infecting the cells.

My laboratory performs this kind of work with SARS-CoV-2 and other emerging viruses. Researchers have used these well-established techniques to test out antibodies after COVID-19 recovery, as well as different vaccines and different variants.

If antibodies people made against prior variants can’t stop omicron from infecting lung cells in the lab, then those antibodies probably won’t protect people out in the world either.

The very first early results are starting to come back, and it looks like antibodies against earlier variants are less successful at blocking omicron. Researchers took antibodies from six people who each had two doses of vaccine and from six other people who each had two doses of vaccine and had also recovered from an earlier COVID-19 infection. Antibodies from both groups of people were about 40 times worse at stopping omicron than original SARS-COV-2 strains, based on how much antibody was needed to prevent infection. But the people whose immune systems had seen the virus three times – that is, were doubly vaccinated and had also recovered from COVID-19 – had antibody levels that were high enough to still stop infection.

I’d expect people who have received booster vaccines will have similar or greater levels of immunity and will be at least moderately protected from omicron. But it will need to be tested. Pfizer has said their early results agree with this prediction, but the data is not yet publicly available. All of this work is not yet peer reviewed and still very preliminary.

Scientists will need to determine how a drop in “neutralization titer,” or how good antibodies are at blocking the virus in the lab, corresponds to a drop in “vaccine effectiveness” or how likely a vaccinated person is to get COVID-19 compared to an unvaccinated one. Scientists know that better antibodies correspond to more effective vaccines, but the precise numerical relationships need to be determined.

How contagious is omicron compared to delta?

The past pandemic year has shown that contagiousness, or transmissibility, has been the key factor in determining whether a coronavirus variant becomes dominant. Delta’s transmissibility has made it the current dominant variant because it simply outran others. But that situation may change with time.

The basic elements of the viral “life” cycle are getting into cells, making more virus, and getting out. Scientists can measure each of these stages in the lab and report what aspects of a variant make it more or less transmissible. In addition to binding to human cells better, some mutations enhance the packaging of new virus and the delivery of its genes once the virus gets into the cell.

While lab-based science can help people understand the biology behind just why a variant is more or less contagious, right now nature is doing a much bigger real-world experiment. Disease surveillance data from the U.K. and other countries where delta has been dominant suggest that omicron is gaining share and may eventually displace delta.

Exactly how this plays out may differ from one country to another, depending on factors like the number of vaccinated people and which variants were previously in circulation, but this news about how good omicron is at spreading is concerning.

Does omicron make people more or less sick?

This is again a question that will be answered much more quickly by the thousands of people infected with omicron than by work in the lab. It’s important to remember, though, that nature’s experiments are not as carefully controlled as lab experiments. Precise lab work will help explain why omicron might be different, but the first answers here will come from hospitals.

Lab-based scientists will be working with hospitals to analyze what makes some patients more or less sick once they contract omicron. Some early numbers suggest that the first omicron cases are mostly mild, but public health officials urge caution: Most cases of all COVID-19 variants are mild, and many of those infected so far with omicron are younger. Hospitalization counts tend to increase somewhat after the initial increase in cases. So this question will take time to answer.

How are lab data and public health data complementary?

Laboratories will provide the first results on immune protection against omicron, although this will be followed up with public health data that will likely confirm the lab results. Public health data will bring the first results on contagiousness and disease severity, which will then be explained by laboratory results.

Once the initial answers from public health data are in, laboratory results are still important to understand why these changes happened and to help predict what future variants will do. How do officials declare a variant of concern in the first place? It’s a combination of public health data and understanding from the lab.

What do we know already?

Variants of SARS-CoV-2 don’t change the laws of physics and biology. They cannot leap tall buildings in a single bound. Physical barriers like high-grade masks and good ventilation will still stop the virus. And, very likely, vaccines will continue to provide some amount of protection. The question is how much, and whether the world needs to change the current vaccines or just provide more of them.

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Peter Kasson, Associate Professor of Molecular Physiology and Biomedical Engineering, University of Virginia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Each season, the celebration of Christmas has religious leaders and conservatives publicly complaining about the commercialization of the holiday and the growing lack of Christian sentiment. Many people seem to believe that there was once a way to celebrate the birth of Christ in a more spiritual way.

Such perceptions about Christmas celebrations have, however, little basis in history. As a scholar of transnational and global history, I have studied the emergence of Christmas celebrations in German towns around 1800 and the global spread of this holiday ritual.

While Europeans participated in church services and religious ceremonies to celebrate the birth of Jesus for centuries, they did not commemorate it as we do today. Christmas trees and gift-giving on Dec. 24 in Germany did not spread to other European Christian cultures until the end of the 18th century and did not come to North America until the 1830s.

Charles Haswell, an engineer and chronicler of everyday life in New York City, wrote in his “Reminiscences of an Octoganarian” that in the 1830s German families living in Brooklyn dressed up Christmas trees with lights and ornaments. Haswell was so curious about this novel custom that he went to Brooklyn in a very stormy and wet night just to see these Christmas trees through the windows of private homes.

The first Christmas trees in Germany

Only in the late 1790s did the new custom of putting up a Christmas tree decorated with wax candles and ornaments and exchanging gifts emerge in Germany. This new holiday practice was completely outside and independent of Christian religious practices.

The idea of putting wax candles on an evergreen was inspired by the pagan tradition of celebrating the winter solstice with bonfires on Dec. 21. These bonfires on the darkest day of the year were intended to recall the sun and show her the way home. The lit Christmas tree was essentially a domesticated version of these bonfires.

The English poet Samuel Taylor Coleridge gave the very first description of a decorated Christmas tree in a German household when he reported in 1799 about having seen such a tree in a private home in Ratzeburg in northwestern Germany. In 1816 German poet E.T.A. Hoffmann published his famous story “Nutcracker and Mouse King.” This story contains the very first literary record of a Christmas tree decorated with apples, sweets and lights.

From the onset, all family members, including children, were expected to participate in the gift-giving. Gifts were not brought by a mystical figure, but openly exchanged among family members – symbolizing the new middle-class culture of egalitarianism.

From German roots to American soil

American visitors to Germany in the first half of the 19th century realized the potential of this celebration for nation building. In 1835 Harvard professor George Ticknor was the first American to observe and participate in this type of Christmas celebration and to praise its usefulness for creating a national culture. That year, Ticknor and his 12-year-old daughter Anna joined the family of Count von Ungern-Sternberg in Dresden for a memorable Christmas celebration.

Other American visitors to Germany – such as Charles Loring Brace, who witnessed a Christmas celebration in Berlin nearly 20 years later – considered it a specific German festival with the potential to pull people together.

For both Ticknor and Brace, this holiday tradition provided the emotional glue that could bring families and members of a nation together. In 1843 Ticknor invited several prominent friends to join him in a Christmas celebration with a Christmas tree and gift-giving in his Boston home.

Ticknor’s holiday party was not the first Christmas celebration in the United States that featured a Christmas tree. German-American families had brought the custom with them and put up Christmas trees before. However, it was Ticknor’s social influence that secured the spread and social acceptance of the alien custom to put up a Christmas tree and to exchange gifts in American society.

The introduction of Santa Claus

For most of the 19th century, the celebration of Christmas with Christmas trees and gift-giving remained a marginal phenomenon in American society.

Most Americans remained skeptical about this new custom. Some felt that they had to choose between older English customs such as hanging stockings for presents on the fireplace and the Christmas tree as proper space for the placing of gifts.

It was also hard to find the necessary ingredients for this German custom. Christmas tree farms had first to be created. And ornaments needed to be produced.

The most significant steps toward integrating Christmas into popular American culture came in the context of the American Civil War.

In January 1863 Harper’s Weekly published on its front page the image of Santa Claus visiting the Union Army in 1862. This image, which was produced by the German-American cartoonist Thomas Nast, represents the very first image of Santa Claus.

In the following years, Nast developed the image of Santa Claus into the jolly old man with a big belly and long white beard as we know it today. In 1866 Nast produced “Santa Claus and His Works,” an elaborate drawing of Santa Claus’ tasks, from making gifts to recording children’s behavior. This sketch also introduced the idea that Santa Claus traveled by a sledge drawn by reindeer.

Declaring Christmas a federal holiday and putting up the first Christmas tree in the White House marked the final steps in making Christmas an American holiday. On June 28, 1870, Congress passed the law that turned Christmas Day, New Year’s Day, Independence Day, and Thanksgiving Day into holidays for federal employees.

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And in December 1889 President Benjamin Harrison began the tradition of setting up a Christmas tree at the White House.

Christmas had finally become an American holiday tradition.

Thomas Adam, Associate Professor of International and Global Studies, University of Arkansas

This article is republished from The Conversation under a Creative Commons license. Read the original article.