Coronavirus in Baltimore-Washington region shows little change, supporting need for one global vaccine

New research from the Johns Hopkins Applied Physics Laboratory confirms that the coronavirus has not significantly changed since it began infecting people widely in the Baltimore-Washington area in March, boosting the view that one vaccine should help prevent it.

Scientists looked at the genetic makeup of the virus, with samples taken from dozens of patients at Johns Hopkins Medicine, where early on more than a third of those infected were treated for COVID-19, the disease caused by the coronavirus.


There were many small genetic differences in the samples, meaning people likely brought the virus from many different places, though most likely came from Europe or passed through that continent. Similar evidence was found in a study of the virus in the New York area earlier this year.

“Because the virus had just emerged into the human population, there was an expectation there wouldn’t be large changes early on because there was no immunity in the population to cause the virus to change course,” said Peter Thielen, a molecular biologist at the Applied Physics Lab and one of the lead authors on the genetic sequencing work.


“But we’re constantly looking for things that might be an issue with vaccine development,” he said.

Thielen said the findings stand in contrast to the ever-evolving influenza viruses. The mutations mean a new vaccine has to be formulated each year. And they have had varying degrees of effectiveness.

The coronavirus data did not suggest how long someone might be immune to the virus once they have been sick.

It also doesn’t explain why some people get more sick than others, though it’s not different strains of the virus or the amount of virus someone is exposed to, Thielen said.

More research is needed, but the answer is likely age and underlying health conditions, whether people are aware of those conditions or not, he said.

The research was conducted by a cross enterprise team that included APL, the Johns Hopkins School of Medicine, the university’s Whiting School of Engineering and the Bloomberg School of Public Health.

The research team will look now at samples collected during Maryland’s stay-at-home order and others taken during the gradual reopening to see if the lockdown was effective and how it changed patterns of viral transmission in the region.