If G614 truly is more transmissible in equivalently mixing populations, then yes, the virus will be harder to control. But we cannot definitively answer this question at the moment

Now, researchers in the U.S. and U.K. have queried the Global Initiative for Sharing All Influenza Data (GISAID) SARS-CoV-2 sequence database looking for changes in the spike protein genetic sequence of more than 0.3% from the Wuhan reference. Using this criterion, they identified a D614G amino acid change caused by a point mutation.

Examination of viral strains from Europe, North America, Australia, and Asia showed that the G614 variant increased in frequency over a several month period, even when D614 was initially dominant. In time-series analyses, 30 of 31 regions showed an increase in frequency of G614 over D614. Examination of viral sequences from 999 patients hospitalized with COVID-19 showed that the cycle threshold was lower, indicating a higher viral load with the G614 variant than with the D614 virus. Higher viral titers were seen in pseudovirus with the G614 variant than with the D614 variant. However, hospital outcomes were similar with either variant, and convalescent sera from 6 patients demonstrated equivalent or better neutralizing ability against G614 than against D614.

COMMENT

Although SARS-CoV-2 is not highly mutable, these data demonstrate that variants may arise quickly and have profound effects on the COVID-19 pandemic. Even though this variant appears to be more infectious, it did not appear to be more virulent, and, in limited assays, it was still inactivated by convalescent sera. However, continued surveillance and vigilance are required because we may not be as fortunate with the next variant.

As to whether or not natural selection plays a part of which strain becomes more predominant has yet to be seen.

I'd be surprised if we're still wearing masks and 6-feet distancing in two or three years. I think the most likely outcome is that we'll eventually get to herd immunity. The best way to get to herd immunity is through a vaccine and some certain populations who have already been exposed or will be exposed.

And then the expectation I have is that this virus will actually become the next common cold coronavirus. What we don't know with these common cold coronaviruses is if they went through a similar transition period.

So, say something like OC43, which is a common cold coronavirus that was originally from cows. It's been historically reported that there was an outbreak associated with the transition of this virus from cows to humans that was very severe disease, and then after a few years, the virus became just the common cold. So in three to five years it may be that you're still getting COVID-19 in certain populations of people or every few years, but the expectation is hopefully that it'll just be a common cold and it's something that we can just each deal with and it won't lead to hospitalization and the shutting down of society

Immunization with SARS Coronavirus Vaccines Leads to Pulmonary Immunopathology on Challenge with the SARS Virus

• Chien-Te Tseng,
• Elena Sbrana,
• Naoko Iwata-Yoshikawa,
• Patrick C. Newman,
• Tania Garron,
• Robert L. Atmar,
• Clarence J. Peters,
• Robert B. Couch

Published: April 20, 2012

• https://doi.org/10.1371/journal.pone.0035421

Background

Severe acute respiratory syndrome (SARS) emerged in China in 2002 and spread to other countries before brought under control. Because of a concern for reemergence or a deliberate release of the SARS coronavirus, vaccine development was initiated. Evaluations of an inactivated whole virus vaccine in ferrets and nonhuman primates and a virus-like-particle vaccine in mice induced protection against infection but challenged animals exhibited an immunopathologic-type lung disease.

Design

Four candidate vaccines for humans with or without alum adjuvant were evaluated in a mouse model of SARS, a VLP vaccine, the vaccine given to ferrets and NHP, another whole virus vaccine and an rDNA-produced S protein. Balb/c or C57BL/6 mice were vaccinated IM on day 0 and 28 and sacrificed for serum antibody measurements or challenged with live virus on day 56. On day 58, challenged mice were sacrificed and lungs obtained for virus and histopathology.

Results

All vaccines induced serum neutralizing antibody with increasing dosages and/or alum significantly increasing responses. Significant reductions of SARS-CoV two days after challenge was seen for all vaccines and prior live SARS-CoV. All mice exhibited histopathologic changes in lungs two days after challenge including all animals vaccinated (Balb/C and C57BL/6) or given live virus, influenza vaccine, or PBS suggesting infection occurred in all. Histopathology seen in animals given one of the SARS-CoV vaccines was uniformly a Th2-type immunopathology with prominent eosinophil infiltration, confirmed with special eosinophil stains. The pathologic changes seen in all control groups lacked the eosinophil prominence.

Conclusions

These SARS-CoV vaccines all induced antibody and protection against infection with SARS-CoV. However, challenge of mice given any of the vaccines led to occurrence of Th2-type immunopathology suggesting hypersensitivity to SARS-CoV components was induced. Caution in proceeding to application of a SARS-CoV vaccine in humans is indicated.

World Health Organization officials said AstraZeneca’s decision to delay the phase three trial of its experimental Covid-19 vaccine for safety reasons is a reminder that vaccine development is “not always a fast and a straight road.”

AstraZeneca’s announced Tuesday that it was placing a hold on stage three human trials for its potential vaccine, which it’s developing alongside the University of Oxford, after one of the participants showed signs of a potential serious adverse reaction, which was first reported by STAT News. The company told CNBC that the delay was a “routine action” whenever there’s an unexplained illness under investigation.

WHO Chief Scientist Dr. Soumya Swaminathan said Thursday that there’s no need to be “overly discouraged” by the news, adding that “these things happen.”

“There’s a protocol for what you do when something happens,” Swaminathan said during a news briefing at the organization’s Geneva headquarters. “If it’s a mild side effect, there are things to be done. If it’s major as it was in this case — it was a severe side event — and therefore the trial was halted. And again this is normal procedure. This is good clinical practice because safety is of the upmost, highest priority in any clinical trial.”

While the WHO hopes the vaccine’s trials will resume soon, it must wait for more information provided by a data and safety monitoring board, which will determine how to proceed with the trials, Swaminathan said.

“I think this is a good ... perhaps a wake-up call or a lesson for everyone to recognize the fact that there are ups and downs in research, there are ups and downs in clinical development and we have to be prepared for those,” she said. “We hope that things will be able to move on but again it depends. It depends on a lot, and we have to wait to see the details of what actually happened.”