Coronavirus vaccine safe in early trial, hydroxychloroquine may increase death risk

Modesto Morganelli
Mag 24, 2020

Further trials are needed to determine whether the vaccine effectively protects against infection - rather than just triggers an immune response to the virus. The paper revealed the results of phase 1 clinical trials of the adenovirus vector-based vaccine they are developing in collaboration with the Beijing Institute of Biotechnology.

"These results should be interpreted cautiously".

Even if the vaccine developed by Moderna passes successfully through all stages of testing, or whenever a vaccine does, the next challenges we will face are first the logistical and then the geopolitical.

In the desperate early days of the coronavirus pandemic, reports from China that few critically ill COVID-19 patients could be revived after a cardiac arrest led doctors in some countries to consider issuing blanket "Do Not Resuscitate" orders.

After 28 days, most participants had a four-fold increase in binding antibodies (35/36, 97% low-dose group; 34/36 (94%) middle-dose group, and 36/36, 100% in high-dose group), and a half (18/36) of participants in the low- and middle-dose groups and three-quarters (27/36) of those in the high-dose group showed neutralizing antibodies against SARS-CoV-2.

Promising results from the completed first human trial China's Ad5 coronavirus vaccine place it at the front of the global race for a shot, though only by a slim margin, an expert told It utilizes a weakened common cold virus to convey genetic material that codes for the SARS-CoV-2 spike protein to the cells.

The trial was created to assess the vaccine's safety and its capacity to generate an immune response when given to 108 healthy adults aged 18 and 60 years who have not been infected by the virus. The volunteers were assigned to receive either a single injection of the new Ad5 vaccine at a low dose, middle dose, or a high dose, they said. "Humoral responses against SARS-CoV-2 peaked at day 28 post-vaccination in healthy adults, and rapid specific T-cell responses were noted from day 14 post-vaccination", the study stated.

"We showed that vaccines induce antibodies, and the vaccinated animals are protected either partially or fully", he said.

The most common side effects were mild pain at the injection site, mild fever, fatigue, headache and muscle pain, the study said. These reactions occurred within a day after vaccination and did not persist for more than two days. An open-label trial of 108 healthy adults showed good results after 28 days.

A majority of participants also produced virus-fighting T cells two weeks after taking the vaccine, which were also greatest at the higher dose levels. Mean titer for neutralising antibody in the high-dose group was noted to be 34.0, while it stood at 16.2 in the middle and 14.5 in the low-dose group.

In these people, "their immune systems will essentially rear up and blunt the effect of the vaccine", said Dr. Kirsten Lyke, a vaccinologist at the University of Maryland who is leading another coronavirus vaccine trial.

"Our study found that pre-existing Ad5 immunity could slow down the rapid immune responses to SARS-CoV-2 and also lower the peaking level of the responses".

Dr Daniel Barouch, director of vaccine research at Beth Israel Deaconess Medical Center in Boston, who was not involved in the work, acknowledged that "this is a promising data" but added that it is "early data".

Citing the main limitations of the trial, the authors said the study had a small sample size and was conducted in relatively short duration, with a lack of randomised control group.

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