Unvaccinated people are ‘variant factories’, infectious disease expert says
This is because the only source of new coronavirus variants is the body of an infected person.
“Unvaccinated people are potential variant factories,” Dr. William Schaffner, professor in the Division of Infectious Diseases at Vanderbilt University Medical Center, told CNN on Friday.
âThe more people who are unvaccinated, the more likely the virus is to multiply,â said Schaffner, a professor in the division of infectious diseases at Vanderbilt University Medical Center.
“When it does, it mutates, and that could trigger a variant mutation which is even more serious down the road.”
All viruses mutate, and while the coronavirus is not particularly prone to mutations, it does change and evolve.
Most of the changes don’t mean anything to the virus, and some can weaken it. But sometimes a virus develops a random mutation that gives it an advantage – better transmissibility, for example, or more efficient replication, or an ability to infect a wide variety of hosts.
Viruses with an advantage will outshine other viruses and eventually make up the majority of virus particles infecting someone. If that infected person passes the virus on to someone else, they will pass the mutant version.
If a mutant version is successful enough, it becomes a variant.
But for that, it must replicate. An unvaccinated person offers this possibility.
“As mutations appear in viruses, the ones that persist are those that facilitate the spread of the virus in the population,” Andrew Pekosz, microbiologist and immunologist at the Johns Hopkins Bloomberg School of Public Health, told CNN.
“Every time the viruses change, it gives the virus a different platform to add more mutations. Now we have viruses that spread more efficiently.”
Viruses that do not spread cannot mutate.
Variants have appeared all over the world – the B.1.1.7 or Alpha variant was first seen in England. The B.1.351 or Beta variant was first spotted in South Africa. The Delta variant, also known as B.1.617.2, was first seen in India. And the United States has released several of its own variants, including the B.1.427 or Epsilon line first seen in California and the B.1.526 or Eta variant first seen in New York.
Already, a new variant has swept across much of the world. Last summer, a version of the virus carrying a mutation called D614G passed from Europe to the United States and then to the rest of the world. The change made the virus more efficient – it replicated better – so this version took over from the original strain that emerged from China. It appeared before people started naming the variants, but it has become the default version of the virus.
Most of the newer variants have made modifications to the D614G. The Alpha variant, or B.1.1.7, became the dominant variant in the United States in late spring due to its additional transmissibility. Now the Delta variant is even more heritable, and it is fast becoming the dominant variant in many countries, including the United States.
Current vaccines protect well against all variants so far, but that could change at any time. That’s why doctors and public health officials want more people to get vaccinated.
“The more we allow the virus to spread, the more opportunity the virus has to change,” advised the World Health Organization last month.
Vaccines are not widely available in many countries. But in the United States, supply is plentiful, with demand slowing. Only 18 states have fully immunized more than half of their residents, according to data from the U.S. Centers for Disease Control and Prevention.
âCurrently, about 1,000 counties in the United States have vaccine coverage below 30%. These communities, primarily in the Southeast and Midwest, are the most vulnerable. In some of these areas we are already seeing increased rates of disease. CDC director Dr Rochelle Walensky said Thursday during a White House briefing.
âWhenever we see the virus circulating in the population, especially a population that has pockets of immune people, vaccinated people, and pockets of unvaccinated people, you have a situation where the virus can probe,â Pekosz said. .
If a virus tries to infect an immune person, it can fail or succeed and cause a mild or asymptomatic infection. In this case, it will replicate in response to pressure from a primed immune system.
Like a bank robber pictured all over the wanted posters, the virus that succeeds will be the virus that makes a random change that makes it less visible to the immune system.
These populations of unvaccinated people give the virus change not only to spread, but to change.
“All it takes is a mutation in a person,” said Dr. Philip Landrigan, pediatrician and immunologist at Boston College.