Weekly Covid-19 Update: Wednesday, December 15, 2021

Apologies for my absence from these reports. The last two months have been absolutely insane from a work and personal life perspective. I’ve been reading so much about Omicron lately and thought I should try to do at least a brief update! I will try to get back to doing these every Tuesday for a while moving forward. Without further ado, here is the latest in Covid-related research and news.

1) The first thing on most of your minds is probably whether vaccines are effective against the new Omicron variant. Remember that research takes time and we are still in the early days of this variant, but there are some initial findings to report. I’ll include these in points 1, 2, and 3 of this update. First, a very small study out of South Africa, which has not yet been peer reviewed, studied 12 people infected with Omicron (6 with no previous infection, 6 with previous infection, all vaccinated with Pfizer). In those with two doses of Pfizer but no previous infection there was a 41-fold lower level of neutralizing antibodies than what was seen with previous variants of the virus. Those who were previously infected and vaccinated showed higher neutralization than those who were only vaccinated, suggesting that booster doses of the vaccine may help to reduce the risk of infection. The authors concluded, “Previous infection, followed by vaccination or booster is likely to increase the neutralization level and likely confer protection from severe disease in Omicron infection.” You can read the pre-print of the study here: https://www.ahri.org/wp-content/uploads/2021/12/MEDRXIV-2021-267417v1-Sigal.pdf

2) Another study conducted in Israel (and for which I cannot find a pre-print, so this information is based on multiple news articles) studied the blood of 20 people who were vaccinated five to six months ago and 20 people who received a booster dose of the vaccine within the last month. Researchers introduced the Omicron variant to the blood, and amongst those who received their vaccine 5–6 months ago there was no neutralization against the variant. For those who had recently received a booster dose, though, there was a large immune response. One of the study’s authors, Dr. Gili Regev-Yochay, said that their findings showed the booster dose was about four times less effective against Omicron than it was against the Delta variant. Still, this study provided some good news regarding the effectiveness of booster doses. You can read a news article about it from The Independent here: https://www.independent.co.uk/news/world/asia/booster-third-jab-omicron-covid-israel-b1974840.html and another one from Reuters here: https://www.reuters.com/world/middle-east/israeli-study-finds-pfizer-covid-19-booster-protects-against-omicron-2021-12-11/

3) A report published by the UK Health Security Agency, which I believe is the largest real-world analysis thus far, compared 56,439 cases of Delta Covid infections with 581 cases of Omicron to help determine vaccine effectiveness against the new variant. After two doses of Pfizer, vaccine effectiveness against Omicron was only 30–40%, and for AstraZeneca there was an even greater reduction. In those who received a Pfizer booster dose, however, there were significant increases in protection against symptomatic infection. For those who initially received two doses of AstraZeneca, the Pfizer booster provided 70% protection and for those who initially received two doses of Pfizer, the booster provided 75% protection. These numbers are lower than the booster’s protection against the Delta variant (around 90%). The report also included data about transmission of the Omicron variant based on data about households and close contacts, finding that the risk of transmission was higher with Omicron cases than it was for Delta. You can read the full report here: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1040076/Technical_Briefing_31.pdf

4) A study published in The Lancet examined booster vaccine effectiveness amongst 2,878 participants in the study, all of whom received a third vaccine dose two to three months after their second vaccine dose of AstraZeneca or Pfizer. The study found that those who originally received AstraZeneca vaccines achieved antibody levels 25 times higher than controls when they received a Pfizer booster and 32 times higher when they received a full dose of a Moderna booster. For those who received their first two doses of Pfizer, they experienced an eightfold increase in antibodies after the Pfizer booster and an 11-fold increase when they received the full dose of the Moderna booster (note — I say “full dose” because in the UK when Moderna is used as a booster, it is only given as a half dose). The findings were similar across all age groups (ages 30–82 were involved in the study). You can read the full peer-reviewed study here: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)02717-3/fulltext

5) Based on findings from a clinical trial conducted by Pfizer, it appears that the company’s antiviral pill to treat Covid, called PAXLOVID, is effective in preventing hospitalization and death. In a study of 2,246 high-risk Covid patients, the drug reduced the risk of hospitalization by 89% within three days of symptom onset and 88% within five days of symptoms. There were no deaths in the sample studied. In both high-risk and standard-risk patients, the drug was shown to result in a 10-fold decrease in the viral load when compared to a placebo drug. Pfizer also announced that its antiviral drug was expected to work against the new Omicron variant of Covid. The company is now seeking approval for the drug from the Food and Drug Administration in the US. You can read the company’s full press release about it here: https://www.pfizer.com/news/press-release/press-release-detail/pfizer-announces-additional-phase-23-study-results

6) A study published by a private nonprofit foundation that conducts independent research on health policies, The Commonwealth Fund, reported that Covid vaccinations in the United States prevented 1.1 million Covid deaths, 10.3 million hospitalizations, and nearly 40 million infections as of November 2021. The researchers utilized modelling taking into account the population demographics of the US, the prevalence of specific Covid variants over different time periods, and daily vaccine doses administered in the US. The study also estimated that without vaccines the daily death toll in the US alone could have reached 21,000 per day. The researchers concluded, “As the Omicron variant begins to spread and the Delta variant surge continues, our results point to the tremendous power of vaccination to reduce disease and death from COVID-19. Sadly, they also highlight the ongoing tragic consequences of failing to vaccinate every eligible American.” You can read the full study here: https://www.commonwealthfund.org/publications/issue-briefs/2021/dec/us-covid-19-vaccination-program-one-year-how-many-deaths-and?utm_source=twitter&utm_medium=social&utm_campaign=Improving+Health+Care+Quality

7) Now for a world update. In the US there were 116,687 new cases of Covid-19 yesterday and over the past two weeks the number of daily new cases has increased 46%. Hospitalizations are up 22% over the same time period and deaths have increased 40%. The US has now reached 800,000 total Covid deaths over the duration of the pandemic. The rate of cases amongst the unvaccinated are 5 times higher than the vaccinated, and deaths amongst the unvaccinated are 13 times higher. In terms of hot spots, Wisconsin leads the nation with the highest rate of cases per capita, followed by New Hampshire, Rhode Island, Maine, Michigan, Connecticut, Massachusetts, Indiana, and Pennsylvania. Amongst all age groups, 61% of Americans are fully vaccinated.
— Today the UK hit its highest daily number of cases EVER with 78,610. Between yesterday and today the number of new cases identified as Omicron increased 87% in England and 140% in Scotland. In a public briefing this evening Professor Chris Whitty, the government’s Chief Medical Advisor, said the UK currently has “two epidemics on top of one another” with Omicron cases rapidly increasing and Delta cases remaining flat. Dr Jenny Harries, the head of the UK Health Security Agency also said today that the Omicron variant is “probably the most significant threat we’ve had since the start of the pandemic”. Of all of those eligible for vaccines in the UK, 81.5% have been fully vaccinated and 43% have received a booster dose.
— Elsewhere, Australia’s state of New South Wales recorded its highest number of new daily cases in three months with 1,360. Of those, 110 were confirmed to be the Omicron variant. From today, NSW removed most Covid restrictions for unvaccinated people in the state.
US data: https://www.nytimes.com/interactive/2021/us/covid-cases.html
UK data: https://www.theguardian.com/politics/live/2021/dec/15/uk-covid-live-news-coronavirus-omicron-boosters-vaccines-christmas-boris-johnson-latest-updates and https://coronavirus.data.gov.uk/details/vaccinations
Australian update: https://edition.cnn.com/2021/12/14/australia/australia-omicron-covid-outbreak-restrictions-intl-hnk/index.html

That’s all for today. I will try to be back on my regular day (Tuesday) next week with a new update!



Weekly wrap-up of the latest Coronavirus research and news for those who want a one-stop shop for peer-reviewed research findings written in a way that is easy to understand.

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store