81 Percent of Clinical Trial Volunteers Suffer Reactions to CanSino Biologics’ COVID-19 Vaccine That Uses HEK293 Human Fetal Cell Lines

81 Percent of Clinical Trial Volunteers Suffer Reactions to CanSino Biologics’ COVID-19 Vaccine That Uses HEK293 Human Fetal Cell Lines

An experimental vaccine for COVID-19 is being developed by CanSino Biologics, Inc. of Tianjin, China, in partnership with China’s Academy of Military Medical Sciences’ Institute of Biotechnology. A Phase 1 human clinical trial of the COVID-19 vaccine (adenovirus type-5 Ad5-nCoV) has been completed in China involving 108 volunteers, ranging in age from 45–60 years old.1 2 3 4

In that trial, 87 (81 percent) of the 108 participants suffered at least one adverse reaction within seven days after vaccination. Of these, 30 of the human subjects were in the low dose group, 30 were in the middle dose group, and 27 were in the high dose group. Overall, 10 of the participants experienced Grade 3 adverse reactions. Of the 36 participants in the high dose group, six of them had Grade 3 adverse reactions.1 2

Pain, Fever, Fatigue, Headache Most Common Reactions to CanSino’s Ad5-nCoV Vaccine for COVID-19

According to researchers conducting the study on the Phase 1 clinical trial for the Ad5-nCoV vaccine:

The most common injection site adverse reaction was pain, which was reported in 58 (54%) vaccine recipients. Pain was reported in 17 (47%) participants in the low dose group, 20 (56%) participants in the middle dose group, and 21 (58%) participants in the high dose group. The most commonly reported systematic adverse reactions overall were fever (50 [46%]), fatigue (47 [44%]), headache (42 [39%]), and muscle pain (18 [17%]). Fever was reported in 15 (42%) participants in the low dose group, 15 (42%) participants in the middle dose group, and 20 (56%) participants in the high dose group. Headache was reported in 14 (39%) participants in the low dose group, 11 (31%) participants in the middle dose group, and 17 (47%) participants in the high dose group. Muscle pain was reported in seven (19%) participants in the low dose group, three (8%) participants in the middle dose group, and eight (22%) participants in the high dose group.2

Nine of the participants, including two in the low dose group, two in the middle dose group and five in the high dose group developed Grade 3 fevers of over 101.3°F. One of the participants in the high dose group reported “severe fever along with severe symptoms of fatigue, dyspnoea, and muscle pain.” Another participant in the high dose group experienced “severe fatigue and joint pain.” The reactions happened within 24 hours after vaccination.1 2

Moderna’s Experimental mRNA-1273 COVID-19 Trials Also Noted Grade 3 Reactions

Like in the Phase 1 Ad5-nCov vaccine trial conducted by CanSino, some participants in the Phase 1 trial of the mRNA-1273 COVID-19 vaccine conducted by Moderna, Inc. earlier this year also experienced Grade 3 reactions. Of the 45 volunteers who participated in the Moderna clinical trial during March-May 2020, nine percent of them experienced severe adverse reactions to the mRNA-1273 vaccine, including 29-year-old Ian Haydon of Seattle, Washington.1 2

Haydon suffered Grade 3 reactions 12 hours after getting the second of two 250 µg doses of the mRNA-1273 vaccine. He developed a fever of over 103 degrees and eventually fainted.1 2

Grade 3 reactions are described by the U.S. Department of Health and Human Services (HHS) as, “severe or medically significant but not immediately life-threatening; hospitalization or prolongation of hospitalization indicated; disabling; limiting self care” such as “bathing, dressing and undressing, feeding self, using the toilet, taking medications.” The only thing worse than Grade 3 events are those classified as Grade 4, which is “life-threatening” and “Grade 5, which is “death.”56 7

CanSino Now Running Phase 2 Human Clinical Trials on Ad5-nCoV Vaccine for COVID-19

CanSino Biologics has reportedly begun a Phase 2 human clinical trial of Ad5-nCoV vaccine using the HEK293 cell line that involves testing on 500 healthy volunteers. On May 12, the National Research Council of Canada (NRC) announced a collaborative agreement with the Chinese company to “advance bioprocessing and clinical development in Canada” of the Ad5-nCoV vaccine.4 8 9 10

In a press release, the NRC stated, “This collaboration will allow the NRC to advance a scale-up production process for the vaccine candidate, using its proprietary HEK293 cell line.”910

To facilitate this work, the Canadian government announced it would provide $44 million to upgrade the NRC facilities in Montreal to “enable compliance with Good Manufacturing Practice (GMP) standards” and to “ensure readiness for Canadian bioprocessing of potential vaccine candidates as they become available.”9

“It is perfect timing to leverage cutting-edge technology and resources from both sides that are critical to the development of Ad5-nCoV,” said Xuefeng Yu, CEO of CanSino Biologics.10

CanSino Ad5-n-CoV Vaccine Uses HEK-293 Human Fetal Cell Lines for Production

Life Site News reported on June 26, 2020 that CanSino’s Ad5-n-CoV vaccine employs a chimpanzee adenovirus vector that uses the HEK293 cell lines derived from tissue of an aborted fetus.11 The HEK293 human fetal cell line, which was designed, developed and is licensed by Canada’s National Research Council (NRC), is also being used to produce the AZD1222 COVID-19 vaccine developed by the University of Oxford’s Jenner Institute.

The May 12, 2020 joint press release issued by Canada’s NRC and CanSino Biologics, Inc. stated,“The relationship between the NRC and CanSinoBIO was first established in 2013. The NRC’s HEK293 cell line was later licensed to CanSinoBIO and used in the development of an approved vaccine against the Ebola virus.”12

According to News Medical:

The HEK293 cell line was initially produced in 1973 by a team led by Alex van der Eb in Leiden (Netherlands) from normal fetal human embryonic kidney cells. These cells were created following transfection with sheared adenovirus 5 DNA, leading to the incorporation of some of the adenoviral genome into the human chromosome 19 of the fetal cell’s genome. The name 293 comes from the fact that it was Frank Graham’s (one of van de Eb’s postdoc) 293rd experiment. These cells were initially thought to originate from an endothelial, epithelial, or fibroblastic cell from the fetal kidney. However, recent evidence into the cellular characteristics of HEK293 cells has led to the suggestion that they may actually originate from a neuronal fetal kidney cell. Following sequencing studies, it has also been identified that these cells have a very complicated karyotype, with multiple copies of chromosomes. For example, these cells have four copies of chromosome 17. It has also been established that these cells do not have a single Y chromosome—but have three X chromosomes—suggesting that the fetus from which they were obtained was a female.13

The HEK293 cell is described by Creative Biolabs this way:

The Human Embryonic Kidney 293 (HEK293) cell line is a predominant host for both stable expression and transient expression of various research grade proteins and protein therapeutics, and more recently, five therapeutic agents produced in HEK293 cells have been approved by the FDA or the European Medicines Agency (EMA) for therapeutic use. Since being generated over 40 years ago, the HEK293 cell line has been extensively used as a robust and reliable platform to produce plenty of recombinant antibodies, antibody fusion proteins and proteins important to the neuropharmacologist, such as G protein coupled receptors, ligand-gated ion channels, and voltage sensitive ion channels. The HEK293 cell line was originally generated by the transformation of normal human embryonic kidney (HEK) cells following exposure to sheared fragments of human adenovirus type 5 (Ad5) DNA. The E1A adenovirus gene is expressed in these cells and participates in transactivation of some viral promoters, allowing these cells to produce very high levels of protein.14


1 Branswell H. Early study of Covid-19 vaccine developed in China sees mixed results. STAT May 22, 2020.
2Hou LH, et al. Safety, tolerability, and immunogenicity of a recombinant adenovirus type-5 vectored COVID-19 vaccine: a dose-escalation, open-label, non-randomised, first-in-human trial. The Lancet June 13, 2020; 395 (10240): 1845-1854.
3Liu A. China’s CanSino Bio advances COVID-19 vaccine into phase 2 on preliminary safety data. Fierce Pharma Apr. 10, 2020.
4 U.S. Food and Drug Administration. CanSino Biologics Moves COVID-19 Vaccine Candidate Into Phase 2 TrialFDA News Apr. 14, 2020.
5 Cáceres M. Healthy Clinical Trial Subjects Suffer Grade 3 Side Effects to Moderna’s mRNA COVID-19 Vaccine. The Vaccine Reaction May 24, 2020.
6 Cáceres M. Volunteer Describes His Serious Reaction in Moderna’s mRNA COVID-19 Vaccine TrialThe Vaccine Reaction May 30, 2020.
7 U.S. Department of Health and Human Services. Common Terminology Criteria for Adverse Events (CTCAE). Nov. 27, 2017.
8 Rettner R. Coronavirus vaccine developed in China shows promise after early study in 100 people. Fox News May 27, 2020.
9 Press Release. The National Research Council of Canada and CanSino Biologics Inc. announce collaboration to advance vaccine against COVID-19. National Research Council of Canada May 12, 2020.
10 Dearment A. CanSino Biologics may start clinical development of Covid-19 vaccine in Canada. MedCity News May 13, 2020.
11 Murdoch A. UK university test COVID-19 vaccine derived from aborted fetal cell line in Africa, Brazil. Life Site News June 26, 2020.
12 Bloomberg. NRC of Canada and CanSino Biologics, Inc. announce collaboration to advance vaccine against COVID-19. May 12, 2020.
13 Simmons H. HEK293 Cells: Applications and Advantages. News Medical Jan. 8, 2019.
14 Creative Biolabs. HEK293 Cell Lines. 2020.


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