Fact Check-Chinese study made coronavirus antibodies in eggs by vaccinating hens

A 2021 study in China investigated antibodies generated by immunizing hens with a specific protein from the SARS-CoV-2 virus and found that the antibodies extracted from yolks could neutralize some versions of the coronavirus tested in the lab.

The results do not mean that all egg yolks contain coronavirus-neutralizing antibodies or that eating eggs would prevent COVID-19, as suggested in some widely shared posts online.

“So EGGS prevent COVID. Do you see it yet?,” reads one Feb. 2 comment on Twitter attaching an extract of the paper that has garnered over 3,600 retweets (here). Other examples can be seen on Instagram (here) (here).

Posts refer to a study originally published in November 2020 (here), which analyzed immunoglobulin Y (or lgY) antibodies generated in the yolks of eggs from laying hens that had been immunized with the “spike” protein from SARS-CoV-2. The researchers then tested the antibodies in human cells in the lab and found that they could block versions of a mock SARS-CoV-2 virus, and even SARS-CoV-1, from binding to the ACE-2 receptor these viruses normally use to enter human cells.

Qinglin Meng, a senior author of the study, did not immediately respond to a Reuters request for comment.

Not all eggs, however, contain the specific antibodies that neutralize SARS-CoV-2, Rodrigo Gallardo, professor in poultry medicine at the UC Davis School of Veterinary Medicine, told Reuters via email.

“Even though all hens and egg yolks contain lgY’s, in order to obtain those that neutralize SARS-CoV-2 you need to immunize (vaccinate) hens with a vaccine containing the virus, proteins, subunits or mRNA from the virus,” he said.

Gallardo coauthored a similar study conducted in 2022 at UC Davis (here) , which found that the purified antibodies from eggs harvested from hens given high doses of the SARS-CoV-2 spike protein could “neutralize” the virus in-vitro (here )

Producing lgY antibodies in eggs by immunizing hens has long been used as a way to generate large quantities of antibody quickly for use in treating diseases in other animals, as described in a 2011 review of the field (here).

During the pandemic, many researchers have also focused on the potential for employing this relatively inexpensive method to produce lgY antibodies in eggs for use in treating or preventing COVID in humans (, (here) .

Such treatments are not likely to be delivered by having people consume the eggs. Rather, the process would extract and purify the antibodies made in the eggs, then use them like other antibody medications, which are typically given intravenously ( , ( .

Some posts referring to the November 2020 Chinese study (whose final version was formally published in January 2021) conflate the false idea that eggs treat COVID with the rise of egg prices in the United States (here) and even with a large fire that broke out at an egg farm in Connecticut on Jan. 28 (here).

One Twitter user commented, “Yes, that may be why there’s a shortage… very fishi,” and another wrote, “That makes a lot of sense now why egg farms are going up in spoke...(sic).”

According to the U.S. Department of Agriculture, however, a worldwide outbreak of avian flu that has killed millions of commercial chickens is among the causes for the increase in egg prices (here)

Hillandale Farms, operator of the egg farm in Bozrah, Connecticut that is mentioned in some posts, has said the cause of the fire is still being investigated (here). The fire would not impact egg prices, a spokesperson for the Department of Agriculture told NBC Connecticut (here).


Misleading. A study in China immunized hens to generate antibodies against SARS-CoV-2 in their eggs, it did not find that all eggs contain such antibodies or that eggs have any effect on COVID.

This article was produced by the Reuters Fact Check team. Read more about our fact-checking work (here).