Can I get COVID-19 if I am vaccinated?What we know

Clinical trials and hands-on studies have shown that the COVID-19 vaccine is very effective in preventing severe COVID-19.

Some vaccines, including asymptomatic ones, are also very good at preventing infections.

However, scientists are still not completely aware of how the vaccine will reduce the transmission of the virus from vaccinated people to others.

The good news is that studies suggest that vaccines reduce infections to some extent.

Additional research is currently underway that should soon provide better answers to the problem of post-vaccination infection.

The COVID-19 vaccine, which is very effective in preventing coronavirus infection in the first place, helps reduce infection. If you are not infected, you cannot infect the virus.

However, the main goal of clinical trials of the COVID-19 vaccine was to show whether the vaccine would prevent symptomatic infections and, in some cases, moderate or severe COVID-19.

Most trials were not designed to show whether the vaccine also blocks asymptomatic infections, that is, infections that do not cause symptoms.

Since their first study, researchers have conducted additional studies that provide clues as to how well vaccines prevent all infections.

Last week, the US Centers for Disease Control and Prevention (CDC) announced Survey On the actual efficacy of two US-approved mRNA vaccines developed by Pfizer-BioNTech and Moderna-NIAID.

Researchers collected weekly nasal swabs from all participants, whether or not they had symptoms of COVID-19, to see if they had the viral genetic material.

Also, if symptoms appeared, additional nasal swabs and saliva samples were collected.

The vaccine was 90% effective in blocking symptomatic and asymptomatic infections in those who received the vaccine twice, and 80% in those who received the vaccine once.

This means a 90 percent reduction in infections in fully vaccinated people compared to a similar group of unvaccinated people.

Such studies have shown that mRNA vaccines significantly reduce infections, but these are just two of the vaccines available.

All approved vaccines Severe COVID-19 and hospitalization, Oxford-AstraZeneca and Johnson & Johnson Vaccines Block less infections Than the mRNA vaccine.

None of the vaccines are 100% effective in preventing infection. Therefore, even if you are less ill with COVID-19, you can still get an infection and spread the virus to others.

Some studies suggest that even if a vaccinated person has an infection, in this case, at least certain vaccines, the virus may be less infectious.

Several research groups are measuring the “viral load” (concentration of coronavirus particles) in vaccinated people.

Just a while ago the study It turns out that viral load is a good indicator of infectivity.

so Survey An Israeli researcher, published in Nature Medicine in late March, was vaccinated with the Pfizer-BioNTech vaccine, and those who later became infected had a higher viral load than those who infected the unvaccinated. I found it low.

“Results indicate that an infection is occurring 12 [days] After vaccination or longer, the viral load at the time of testing can be significantly reduced, affecting viral shedding and transmission, as well as the severity of the disease, “the author writes.

Other the study Similar results were found.

Since the Nature Medicine study was an observational study, not a randomized controlled trial, many factors may have influenced the results. Results may vary depending on the vaccine.

In addition, low viral load suggests low infectivity, but researchers now say they don’t know the “infection” of people’s coronavirus.

They say that additional research is needed to determine if the vaccine prevents infection.

This includes studies that include contact tracing to see if other close contacts with family, friends, and vaccinated people are indirectly protected from infection.

Researchers from COVID-19 Preventive Network (CoVPN)Headquartered at Fred Hutchinson Cancer Research Center in Seattle, Currently recruiting 12,000 college students participating in this type of research.

This survey is conducted at more than 20 universities nationwide.

Half of the students are randomly selected to receive the Moderna-NIAID vaccine on the day they enroll in the study. The rest will get the first shot after 4 months.

After vaccination, students collect nasal swabs daily for 4 months to see if they are infected. This test detects both symptomatic and asymptomatic infections.

Researchers also track infections that occur in close contact with students in studies with infections. This allows researchers to see if an infected person is unlikely to be infected with the virus.

“The degree of transmission from vaccinated individuals is determined by the rate of infection in close contact,” said Dr. Anthony Fauci, head of NIAID, last month. White House News Briefing, When presenting a study.

“We hope that within the next five months or so, we will be able to answer the very important question of whether vaccinated people will be infected asymptomatically,” he said.

We should get an answer to this question soon, but scientists are concerned about certain things Coronavirus mutant It can reduce the effectiveness of the vaccine and can also affect infection after vaccination.

This includes the B.1.351 variant, which was first detected in South Africa, the P.1 variant, which was first detected in Brazil, and the B.1.526 variant, which is rapidly becoming popular in New York.

For all these variants, E484K.. It may help the virus evade antibodies produced by the immune system. This can also reduce the effectiveness of the vaccine.

Clinical trial The Johnson & Johnson and Novavax vaccines have been shown to be less effective in preventing symptomatological infections with the B.1.351 variant compared to the original coronavirus.

However, both vaccines were still effective in reducing the risk of severe COVID-19.

Certain vaccines seem to work better against some variants.Recently released Pfizer data It shows that the vaccine was very effective in South Africa. The B.1.351 variant is common in South Africa.

In addition, Moderna test An updated version of the vaccine designed to target this variant.

In the future, this type of COVID-19 vaccine booster shot may become commonplace. This is similar to the seasonal influenza vaccine being updated annually to match the influenza virus that is prevalent in the community.

Dr. Bob Wachter, Dean of Medicine, University of California, San Francisco, sharp When thinking about the benefits of vaccines, Twitter states that there are two sets.

First, there are personal benefits such as prevention of serious illness, hospitalization and death.

Second, there are public health benefits. Stopping the infection helps the community by preventing the virus from infecting others, including those at greatest risk.

Once a sufficient number of people in the community have been vaccinated, the risk of infection after vaccination is less of an issue.

Until then, there are other ways to prevent the virus from spreading to others — a method that anyone can use.

“People need to continue doing other things that help prevent infection, such as wearing masks, increasing social distance, and washing their hands,” he said. Dr. Jarod Fox, Orlando Health Infectious Disease Specialist.