Scientists urge caution as they don’t know how vaccinated people spread the virus to others
As more people are getting vaccinated it appears as if the end of the pandemic is in sight. But even though there are nine approved vaccines several of which have been shown to be over 90 percent effective at preventing a person from developing a serious illness from the virus there are other things that researchers don’t fully know yet. One of these is whether someone who has been vaccinated with different vaccines can still carry the virus and infect others.
This is concerning since it means that most people who do contract the virus after being vaccinated will likely be asymptomatic and not know that they are carrying it. A study conducted at the University of Chicago showed that at least 50 percent of new COVID-19 cases are the result of being exposed to people who had no symptoms with over 80 (83 to 87) percent of cases prior to vaccine distribution being asymptomatic.
Why Don’t Researchers Know This Information?
When testing the vaccine, the initial clinical trials focused on toxicity and safety. Next they gathered data on how effective the vaccines were at preventing people from getting seriously ill with the virus.
In normal clinical trails there would have been several other rounds of tests done to determine things like whether the vaccines worked better for some groups of people, the effects of the vaccine on those who have already had the virus and whether the vaccines prevent people from actually contracting the virus or if, like the flu vaccine, it just prevents someone from getting seriously ill when they do contract it.
In this case, however, as there was a need to approve a vaccine as quickly as possible for emergency use, these questions were not investigated. As they were considered secondary to safety and efficacy, researchers currently don’t know how the virus travels between people after they’ve been vaccinated.
Now however, things have changed somewhat due to the new, highly contagious SARS-CoV-2 variants from California, the United Kingdom, South Africa and Brazil with the likelihood that others will develop as the virus mutates to survive. As new variants originate and then spread globally, understanding transmission as it relates to vaccine rollout efforts is crucial.
Does the Vaccine Have to Prevent Infection to Stop Transmission?
The best-case scenario for a vaccine is that it will completely prevent you from contracting a disease. However, that is extremely difficult to do and most vaccines control the severity of an illness should you get it but don’t make it such that you can’t get it at all. However, even if some people get infected without realizing it, being vaccinated can prevent transmission in several ways.
Milder cases mean a lower vial load so with less virus in a person’s system there is less likelihood that it will be spread. Milder or asymptomatic cases also mean that the person will not cough or sneeze as much if at all, the main way the virus is spread. The vaccines help reduce both symptomatic and asymptomatic infections which also will decrease transmissions of the virus since fewer people overall will have it.
Concerns in a Semi Vaccinated World
It will likely be months before health experts have definitive findings regarding viral transmission from vaccinated people to unvaccinated people. That is why experts are recommending that even those who have received both vaccine doses continue to wear a mask and adhere to social distancing practices.
Those who have been vaccinated may be protected (remember that it won’t be effective for about 10 percent of the population). However, they still may be a danger to others. The major worry here is that those who have been vaccinated will feel invulnerable and start displaying behavioral disinhibition, meaning they won’t following safety practices since they don’t believe they can get the virus. But as previously mentioned, they could contract the virus, develop a silent case and infect many others who have not yet been vaccinated.
Health experts have said that our world has changed forever, especially in regards to interpersonal relationships. Similar to the flu, COVID-19 will probably survive and without proper safety measures, people will continue to get mild or asymptomatic cases. If people come to view COVID-19 as less bothersome than a cold, they will fail to worry so much about avoiding contact with others or protecting themselves when they do. This will cause a greater amount of the virus to be circulating, increasing the risk that a dangerous mutation that doesn’t respond to the vaccine will develop.
The good news about this is that since there are so many different vaccines even within individual countries, the chance that a mutation will develop that isn’t stopped by one of them, suggests that mutations will not be able to rage out of control before being stopped. This also says that once the majority of the world has been vaccinated, while the virus may still exist, it is unlikely to turn back into a worldwide pandemic such as the one we are currently experiencing.
With the rollout of the COVID-19 vaccines we are in better shape than we were this time last year. However, we still need to be careful since being vaccinated won’t completely prevent us from contracting the virus and many of these post-vaccination cases will likely be asymptomatic meaning we could spread it without realizing it.
Because of this, and the number of mutant strains that have and are developing, it’s important to continue wearing a mask and engaging in social distancing for the foreseeable future. It’s unclear when our society will be safe enough again for us to return to our pre-COVID-19 lives — or if we will ever really be able to fully do so.