Myths and truths you should know after getting the COVID-19 vaccine
The world has taken a significant step forward with the development of vaccines against COVID-19. These are important for achieving herd immunity. This refers to the indirect protection against an infectious disease, which is achieved when a population becomes immune, either as a result of vaccination or following previous infection.
In that sense, vaccination aims at preparing the body’s immune response to generate memory and facilitate proper control of the pathogen and thus prevent diseases. To achieve this goal, there are currently a number of authorized vaccines, and it is essential to have accurate information about them, to avoid listening to the rumors that circulate from unofficial sources, sowing fears and unjustified doubts.
Since governments are advancing in the immunization race and more and more people are getting the COVID-19 vaccine every day, it is important to know about some myths and truths after getting vaccinated against COVID-19:
There are side effects
True. Side effects are normal responses to the injection of a foreign substance. They may include fever, muscle pain, discomfort where the shot was made, and are mediated by the innate immune response. Thus, COVID-19 vaccines and other ones on the market, can produce side effects when they come into contact with the body as the immune system responds to a vaccine molecules.
It should be clarified that each person develops a more or less strong immune response to vaccines. Therefore, it will not generate the same degree of protection or immunity in all organisms. However, post-vaccination side effects do not refer to the immunity being generated by the body, but to a reaction to external molecules. Indeed, side effects are not a sign of increased immunity.
Thanks to the experience with other vaccines, side effects are currently monitored during the first four months after being vaccinated, explained Carlos Álvarez, coordinator of COVID-19 studies at the WHO during “Ask the expert” webinar. He stated that “given the experience with other vaccines, we know that adverse effects occur mostly during the first three months”.
Vaccine generates immediate protection
False. The vaccine effectiveness starts from the second dose, 15 to 21 days after de first shot.
After receiving both doses of the vaccine, the body needs about two weeks to develop immunity. For single-shot COVID-19 vaccines, it is necessary to wait up to four weeks to develop full immunity.
According to the CDC (Centers for Disease Control and Prevention), the body takes a few weeks to build immunity or protection after getting vaccinated against COVID-19. This means that it is possible for a person to become infected with the virus just before or just after being vaccinated and still get sick. This is due to the fact that, in these cases, the vaccine did not have enough time to generate protection.
Immunity is produced days after vaccination. Therefore, although in principle people are unlikely to develop the disease, they can become infected if they come into contact with the virus.
Another important factor is that the vaccine protects against getting sick from COVID-19, but it does not prevent the virus from entering the body. So, a vaccinated person can potentially transmit the virus without developing the disease.
You can stop wearing a mask
False. Experts say the mask should continue to be worn until herd immunity is achieved. “This data should not push people to think that: We’re going to get vaccinated so we can stop using masks,'” declared Francesca J. Torriani, an infectious disease physician at UC San Diego Health who conducted the California study. She added: “These measures need to continue until a large segment of the population has been vaccinated”.
On the other hand, doctors at the University of North Carolina discovered some asymptomatic cases in vaccinated patients who were tested for the virus. David Wohl, medical director of the vaccination clinic at this center, declared the lack of symptoms may have meant that the vaccine was doing exactly what it’s supposed to do: keep people from getting sick, even if it does not completely impede the virus from infecting them.
A vaccinated person can carry the virus and not feel symptoms, so it is important to continue with self-care measures, such as the use of masks, social distancing and hand washing.
Will people test positive for COVID-19 after being vaccinated?
False. The authorized and recommended COVID-19 vaccines will not cause you to test positive on a COVID-19 viral test, as none of the vaccines contain the live virus responsible for the disease. This means that vaccines cannot cause you to get infected.
The vaccines do not have the live COVID-19 virus and will not cause someone to become infected, because vaccines work by teaching the body’s cells to recognize and fight the virus, should they come into contact with the virus in the future.
This does not mean that vaccinated people cannot get infected. It means that the vaccine will not be the cause of infection and that self-care measures must continue to avoid expanding the chain of infection.
Mixing vaccines increases immunity
False. We have heard that receiving a first dose of COVID-19 vaccine and the second dose of another vaccine manufacturer increases immunity. However, although some scientists suspect that a pair of two different vaccines might work better than two doses of the same vaccine, there is not yet enough evidence to support this theory.
John Moore, a virus expert at Weill Cornell Medical Center, explained that no guarantee of any benefit from combining vaccines will be found in clinical trials. Moore gave the example of the HIV vaccine research. Scientists tried combining viral vectors with proteins without success. However, he said that the story may be different for COVID-19 vaccines.
Vaccination is useless against variants
False. Studies have shown that antibodies in infected or vaccinated patients’ serums are able to hinder the infection by viral variants of susceptible cell lines. This protection against cell infection is called neutralization.
It has not yet been possible to define with certainty an antibody concentration threshold to predict whether or not there is protection; however, experimental and observational results are promising, given that the vaccines used seem to provide protection, even against new variants.
Vaccine can change the appearance of a mammogram
True. COVID-19 vaccines can cause enlarged lymph nodes in the armpit. This appears as white spots on mammograms.
This type of swelling is a normal reaction to the vaccine and usually occurs on the same side of the arm where the shot was given. According to Geeta Swamy, a maternal-fetal medicine specialist and member of the American College of Obstetricians and Gynecologists’ COVID vaccine group, this usually lasts only a few weeks.
Swelling in the armpit constitute a side effect. It has been detected during trials of the Moderna and Pfizer-BioNTech vaccines. In the Moderna study, 11.6% of patients reported that swollen lymph nodes appeared after the first shot, and 16% reported that swelling occurred after the second shot. The incidence for Pfizer-BioNTech appears to be lower, with only 0.3% of patients reported to have experienced this side effect.
After getting vaccinated, it is important to continue with self-care measures and always stay informed from official sources, to avoid paying attention to false rumors on the virus. It is necessary to remember that vaccination is important, in order to protect yourself and those around you, as vaccinated persons continue to be potential transmitters of the virus.
When herd immunity is achieved, the numbers of people infected will drop and the pandemic will be under control. In the meantime, keep in mind that vaccines are an important step forward and as long as you are vaccinated, you may not get COVID-19. And, if you do so, you may not develop severe complications.