Evidence Suggests Covid Vaccines Reduce Transmission: How It Works
Since COVID-19 vaccines began rolling out across the world, many scientists have been hesitant to say they can reduce transmission of the virus.
Their primary purpose is to prevent you from getting really sick with the virus, and it quickly became clear the vaccines are highly efficient at doing this. Efficacy against symptoms of the disease in clinical trials has ranged from 50% to 95% , and similar effectiveness has been reported in the real world.
However, even the best vaccines we have are not perfect, which means some vaccinated people still end up catching the virus. We call these cases “breakthrough” infections. Indeed, between April 10 and May 1, six people in hotel quarantine in New South Wales tested positive for COVID-19, despite being fully vaccinated.
But how likely are vaccinated people to actually pass the virus on, if they do get infected? Evidence is increasing that, not only do COVID-19 vaccines either stop you getting sick or substantially reduce the severity of your symptoms, they’re also likely to substantially reduce the chance of transmitting the virus to others.
But how does this work, and what does it mean for the pandemic?
Vaccinated people are much less likely to pass on the virus
Early evidence from testing in animals, where researchers can directly study transmission, suggested immunization with COVID-19 vaccines could prevent animals passing on the virus.
Myth: Getting The Covid
FACT:The CDC continues to monitor the spread of COVID-19 and makes recommendations for wearing face masks, both for those who are fully vaccinated as well as those who are not fully vaccinated.
The CDC also recommends that masks and physical distancing are required when going to the doctors office, hospitals or long-term care facilities, including all Johns Hopkins hospitals, care centers and offices.
Johns Hopkins Medicines current mask safety guidelines have not changed, and we still require all individuals to wear masks inside all of our facilities.
What Is The Connection Between The Johnson & Johnson Covid
In July 2021, the FDA warned that the Johnson & Johnson COVID-19 vaccine may lead to a small but increased risk of Guillain-Barr syndrome . GBS is a disorder in which the body destroys its own nerve cells. It can lead to muscle weakness and sometimes paralysis, trouble breathing, or, rarely, death. The risk of developing GBS after receiving the J&J vaccine is very low, and benefits of vaccination still far outweigh the risks.
The FDAs warning was based on preliminary reports of about 100 cases of GBS that occurred in people who had received the J&J vaccine. To date, about 12.8 million people in the US have gotten the J&J vaccine. Most of the reported cases occurred in men ages 50 years and older, about two weeks after vaccination.
Almost all required hospitalization because GBS can affect the nerves to chest muscles and the diaphragm, making it difficult to breathe. Most people recover completely from GBS within a few months, but some never regain full strength.
Seek immediate medical attention if you experience any of the following symptoms after receiving the J&J COVID-19 vaccine:
- weakness or tingling sensations, especially in the legs or arms, thats worsening and spreading to other parts of the body
- difficulty walking
- difficulty with facial movement, including speaking, chewing, or swallowing
- double vision or inability to move eyes
- difficulty with bladder control or bowel function.
I Have Been Hearing About Heart Problems In Kids And Young Adults Following The Covid Vaccine Should I Still Get My Child Vaccinated
There has a been a higher-than-expected number of heart inflammation cases after vaccination with the mRNA COVID-19 vaccines, particularly among boys and young men. However, the CDC still strongly recommends that all children 12 years and older be vaccinated.
As of July 12, 2021, 1,047 reports of myocarditis and pericarditis had been reported in people under age 30, particularly in male teens and young adults, after vaccination with the Pfizer/BioNTech or Moderna mRNA vaccines The CDCs Advisory Committee on Immunization Practices has said available data “suggest likely association of myocarditis with mRNA vaccination in adolescents and young adults.” Even with the increased risk, heart inflammation is a rare occurrence.
Myocarditis and pericarditis after vaccination was most common in males ages 16 to 24. Cases tended to occur within several days after the second mRNA vaccine dose. Most people who developed myocarditis or pericarditis had mild cases and recovered completely after treatment.
If your child develops any of the following symptoms within a week of vaccination, seek medical care:
- chest pain
- shortness of breath
- feeling like your heart is beating fast, fluttering, or pounding.
Can I Still Get Covid
Cases of infection post-vaccine, called breakthrough cases, are being reported, but experts stress they are still relatively uncommon. Whats more, its rare to get an infection that results in hospitalization or death once you are fully vaccinated.
According to data collected by the CDC, less than 1 percent of fully vaccinated Americans have been hospitalized or have died from COVID-19. The vast majority of serious illness and death is occurring in unvaccinated individuals.
Breakthrough infections, however, can contribute to the spread of COVID-19. New data show that fully vaccinated people who become infected with the delta variant can pass the virus on to others, which is why health officials now recommend that vaccinated individuals in areas of high community transmission wear a face mask in indoor public settings.
The masking recommendation was updated to ensure the vaccinated public would not unknowingly transmit virus to others, including their unvaccinated or immunocompromised loved ones, CDC Director Rochelle Walensky said.
Can Receiving A Covid
No.Receiving a COVID-19 vaccine will not make you magnetic, including at the site of vaccination which is usually your arm. COVID-19 vaccines do not contain ingredients that can produce an electromagnetic field at the site of your injection. All COVID-19 vaccines are free from metals.
Learn more about the in the COVID-19 vaccinations authorized for use in the United States.
Is It Safe To Get The Covid
The CDC recommends waiting until your symptoms go away and you are no longer isolating. If you happen to be infected, but dont know because you have not yet developed symptoms or you have an infection without symptoms, the vaccine is not likely to be harmful. It would increase your bodys immune response against the virus.
Vaccine Protection And Transmission
COVID-19 vaccines are crucial tools in the pandemic response and protect against severe disease and death. Vaccines provide at least some protection from infection and transmission, but not as much as the protection they provide against serious illness and death. More evidence is needed to determine exactly how well they stop infection and transmission.
After being vaccinated, individuals should continue taking simple precautions, such as physical distancing, wearing a mask, keeping rooms well ventilated, avoiding crowds, cleaning hands, and coughing into a bent elbow or tissue. Get tested if you are sick, even if youve been vaccinated. Check local advice where you live and work. Do it all!
Q: Must Vaccine Providers Give A Hard Copy Of The Authorized Recipient And Caregiver Fact Sheetto The Individual When They Get Their Shot
A: The EUA requires vaccination providers, prior to the individual receiving the vaccine, to communicate to the recipient or their caregiver information consistent with the Fact Sheet for Recipients and Caregivers, and either to provide a copy of the or to direct the individual to the website to obtain the Fact Sheet.
What Are The Expected Long
- Most negative effects occur within 6 weeks of receiving a vaccine, which is why the FDA asked the companies to provide 8 weeks of safety data after the last dose.
- mRNA vaccines: The mRNA in the vaccine breaks down pretty quickly because our cells need a way to stop mRNA from making too many proteins or too much protein. But, even if for some reason our cells did not breakdown the vaccine mRNA, the mRNA stops making the protein within about a week, regardless of the bodys immune response to the protein.Watch a short video of Dr. Paul Offit explaining why COVID-19 vaccines would not be expected to cause long-term side effects.
- Adenovirus-based vaccines: Although the DNA from adenovirus-based vaccines does not break down as quickly as mRNA, the DNA cannot alter our DNA because a gene for the enzyme, integrase, is not present.
Asymptomatic Infections Can Still Transmit The Virus
If the virus enters cells and begins replicating but never causes disease, thats an asymptomatic infection. With presymptomatic infections, on the other hand, a person goes on to develop symptoms and is especially contagious in the days before symptoms appear, says Natalie Dean, an assistant professor of biostatistics at the University of Florida in Gainesville.
We know from contact tracing data unrelated to vaccines that people who never develop symptoms tend to be less infectious, Dean says.
Morrison adds that asymptomatic people probably have an excellent initial immune response to slow down how quickly the virus can copy itself, but not enough that viral replication is completely shut off, she says. Thats why they could still shed virus but were not seeing any disease symptoms.
Supporting that idea is the fact that the severity of COVID-19 disease tends to correlate with the total number of viruses in the body, called viral load, Kindrachuk says. Early research showed that people with lower viral loads transmit less virus, further suggesting that asymptomatic infections are less contagious than symptomatic ones. But less is not zero: People with asymptomatic infections still have replicating viruses in their system that they can transmit to others.
When the vaccines were authorized, experts did not yet know whether the shots could prevent infections entirely or whether vaccinated people could develop an asymptomaticbut still contagiousinfection.
Why Do Kids Need The Covid
While children and teens may not be as likely to get severely ill from COVID-19, it can still happen and, in fact, the average age of hospitalizations has been decreasing, particularly since the oldest members of our communities have been vaccinated. With this in mind, parents and teens should consider the following:
Is It Okay To Donate Blood After Getting The Covid
Giving blood after getting the COVID-19 vaccine will not diminish the resulting immune response, which mostly builds in the lymph nodes near the injection site. Likewise, the American Red Cross does not require a delay following vaccination with the vaccines currently approved for use in the U.S.; however, individuals must know which brand of vaccine they received and show the immunization card if possible. More details about blood donation are available on the ARC website.
If I Am Taking Anticoagulants Can I Get The Covid
Patients on blood thinners are asked to speak with a healthcare provider because the vaccine is given intramuscularly, which increases the risk for bleeding. The vaccine itself does not increase the risk for this group of patients.
Find out more in this Parents PACK article, “Medications and COVID-19 Vaccines: What You Should Know.”
What Are The Coronavirus Vaccine Side Effects
You may have pain in the arm where you got the shot, and you might run a fever and experience body aches, headaches and tiredness for a day or two. Chills, swollen lymph nodes can also occur.
For the vaccines that use two doses, if you have not had COVID-19, the chance of having noticeable side effects is higher after the second shot. Those who have had COVID-19 may experience stronger side effects after the first dose.
Experiencing side effectsdoes not mean that you have COVID-19, but signals that your immune system is responding to the vaccine. These side effects are considerably less risky to your health than having COVID-19, but if they persist, call your doctor and ask about taking over-the-counter pain and fever reducers to help you feel better.
In addition, a small number of people have developed a serious blood clot condition after they received the J&J vaccine, and there have been rare cases of myocarditis associated with the Pfizer and Moderna COVID-19 vaccines.
Read more about coronavirus vaccine safety.
How Long Before A Coronavirus Vaccine Takes Effect
The mRNA vaccines require two doses. While people will have some immunity after the first dose, protection will be most likely about one week after receipt of the second dose.
The adenovirus vaccine requires one dose. While people will have some immunity about two weeks after being vaccinated, protection will be more robust about one month after receipt of the vaccine.
How Do Adenovirus Vector Vaccines Work
Adenovirus vector vaccines take advantage of a class of relatively harmless viruses, called adenoviruses. Some adenoviruses cause the common cold, but others can infect people without causing illness. To use these viruses for vaccine delivery, scientists choose types of adenovirus that do not cause illness and to which most people have not been exposed. They alter the virus by removing two of the genes that enable adenovirus to replicate in people, and they replace one of those genes with the one for the SARS-CoV-2 spike protein.
Find out more about adenovirus vaccines in this Vaccine Update article, Getting Familiar with COVID-19 Adenovirus-replication-deficient Vaccines.
Will Annual Or Booster Doses Of Covid
We are still not certain whether people will need to get additional doses of the COVID-19 vaccine because we are still learning how long immunity lasts after:
Further, the increased presence of variants might affect whether or how often additional doses would be needed. This is one reason scientists are anxious to get as many people vaccinated as possible the more the virus can replicate in people, the greater the chance that it will change in a way that allows it to spread widely even among people who have been vaccinated. With this in mind, scientists are continuing to monitor variants and the ability of currently available vaccines to protect against them.
Myth #2: The Vaccines Dont Really Work That Well They Dont Reduce Virus Transmission
Most experts have been urging people to continue following public health guidelines, including masking and social distancing, even after theyve been fully vaccinated with two doses of the Pfizer or Moderna vaccine or one dose of the Johnson & Johnson vaccine and after enough time has passed for those vaccinations to have taken effect .
The reason for this recommendation is because while the and vaccines have been shown to have 95% efficacy against illness , the clinical trials were not designed to test whether any of the trial participants contracted COVID-19 but showed no symptoms.
The experts are saying that the vaccines do not reduce transmission, but that is an inaccurate statement, Gandhi says. Vaccines have always decreased transmission. What they should be saying is that the clinical trials were not designed to test for asymptomatic infection, but there is every biological reason in the world to believe that they will reduce asymptomatic transmission.
The most convincing evidence, though, is just starting to emerge among real-world data. In Israel, where more than 90% of those age 60 and over have been vaccinated, cases have plummeted in this population, Gandhi notes. Not just hospitalizations, which we expected, but cases as well. Moreover, data from vaccinated health care workers recently published in the Lancet and preprint servers show reduced rates of asymptomatic infection and low viral loads in the nose when swabbing after vaccination.
What Side Effects Will My Child Experience From The Covid
Side effects in children 12 to 15 years of age were similar to what has been found in other age groups, including pain at the injection site, fatigue, headache, fever, chills, muscle pain, or joint pain. Likewise, other than injection site pain, side effects were more common after the second dose compared with the first dose. Most side effects were mild or moderate.
No one in the study experienced an allergic reaction following vaccination, but this age group is not less likely to experience such a reaction; therefore, teenagers should remain at the site where the vaccine was given for 15 or 30 minutes based on their risk and history with severe allergic reactions using the same guidance offered for adults.
Recently, a small number of cases of myocarditis, or heart inflammation, have been identified in teens and young adults, particularly in the 4 days after receipt of the second dose of the vaccine. Chest pain, shortness of breath, or related symptoms should be reported to a healthcare provider, so that teens can be appropriately diagnosed and treated. Find out more in this video.
Find additional information:
I Recently Spent Time With Someone Who Tested Positive For Covid
Yes, you do. In July 2021, the CDC recommended that anyone who is fully vaccinated and comes into contact with someone who has, or is suspected of having, COVID-19 should get tested three to five days after exposure. In addition, you should wear a mask in public indoor settings for 14 days or until you receive a negative test result. If you are vaccinated, you do not need to quarantine, but you should isolate if you develop symptoms or receive a positive test result.
Previously, the CDC had said that someone who was fully vaccinated only needed to get tested after exposure if they were experiencing symptoms. The change follows new evidence regarding the Delta variant, which shows that people who are vaccinated and then get infected can spread the virus to others, perhaps to the same extent as those who are unvaccinated.
If you are not fully vaccinated, a 14-day quarantine remains the best way to avoid spreading the virus to others after you’ve been exposed to someone with COVID-19. According to CDC guidelines, you may discontinue quarantine after a minimum of 10 days if you do not have any symptoms, or after a minimum of seven days if you have a negative COVID test within 48 hours of when you plan to end quarantine.
Could The Mrna Vaccines From Pfizer And Moderna Cause The Same Clotting Problem As The J&j Vaccine Did
The Johnson & Johnson /Janssen COVID-19 vaccine is an adenovirus vector vaccine, which is different from the Pfizer and Moderna mRNA vaccines. At the time of the J&J/Janssen pause, more than 182 million doses of the mRNA vaccines had been administered and no cases of thrombosis with thrombocytopenia syndrome, or TTS, had been reported. Three people out of about 85 million doses of Moderna had blood clots, but they did not have low platelets. The number of blood clots experienced by those who got the Moderna vaccine would be expected based on the background rate of clotting in the general population.
If A Person Has Allergic Reactions To A Food Or Medication Can They Get The Vaccine
People with severe allergies to a COVID-19 vaccine ingredient or a previous dose of COVID-19 vaccine should not get that type of COVID-19 vaccine . They may be able to get the alternative type after consultation with an allergist or immunologist. Individuals with a known allergy to polysorbate should not get the COVID-19 vaccine made by Johnson & Johnson/Janssen.
People with immediate allergic reactions to an injectable medication can most often get the COVID-19 vaccine; however, they should remain at the site where they were vaccinated for 30 minutes of observation, instead of the 15 minutes that the general public is recommended to wait. Anyone with this type of allergy who has questions or concerns should discuss the situation with their healthcare provider to assess the potential risks and benefits of receiving the COVID-19 vaccine.
People who have had an anaphylactic reaction to anything else are allowed to get the COVID-19 vaccine, but should remain at the site where the injection was given for 30 minutes, instead of the 15 minutes that the general population are recommended to wait.
If a person with history of allergies continues to have concerns about whether or not it is safe to get the COVID-19 vaccine, they should contact their primary care provider or allergist, who has the benefit of their complete medical history and will, therefore, be in the best position to discuss any potential risks and benefits for that individual.
Will The Spike Protein From Current Vaccines Cause An Issue If There Are Future Variants
This question has two aspects longevity of the spike protein and effects of current immune responses to future variants. While related, these are not cumulative issues, meaning they involve separate considerations:
- Longevity of the spike protein – The spike protein does not remain in the body for an extended time, nor does it travel around the body. The only thing that remains after the vaccine is processed are antibodies and memory immune cells that will recognize the virus if we are exposed in the future. The antibodies and memory cells will or will not recognize the variant spike protein. If they do, great we will have some protection. If they dont, it will be just like an antibody to flu or measles, it will have no effect.
- Effects of current immune responses to future variants – As the virus evolves, it changes, so we might find ourselves dealing with different versions of the virus in the future. Current variants have not changed significantly enough that our antibodies have stopped being protective, so for now, we do not need additional doses of vaccine. If, however, one of these variants changes enough that the vaccine-induced immunity is no longer protective, we will need to make new COVID-19 vaccines that protect against the new version of the virus. As described above, in this scenario the existing immunologic memory will no longer be effective, but it will not be problematic either. A new vaccine would induce new immunity and the process would begin anew.
We Now Know More Than Ever About Covid
The Covid-19 vaccines were initially tested against the original version of the coronavirus, and they performed incredibly well. But delta has proven somewhat more capable of evading the vaccines and may cause more severe illness than its predecessors, based on early research out of the United Kingdom, one of the first places where delta took hold. The new CDC data is a big step forward because it brings our understanding of the vaccines closer to the present.
One of this weeks CDC studies tracked new cases and hospitalizations from early May to late July in New York. The study period covers the transition from the alpha variant to delta, which became dominant by the start of July, but only includes part of the recent surge in reported cases.
The vaccines grew less effective in preventing all illness as the delta variant took over, CDC researchers found. In May, vaccines had an estimated 90 percent effectiveness at preventing new cases. By mid-July, the estimated effectiveness had dropped to just under 80 percent. By that point, vaccinated people were more likely to get infected and actually feel sick. Breakthrough infections became more common.
But the vaccines have remained resilient against severe symptoms, with the estimated effectiveness against hospitalization holding steady around 95 percent from the start to the end of the study period.
Vaccinated people should still feel confident that they are protected against the worst outcomes from Covid-19
Is Covid Different In The Vaccinated
The latest data from Public Health England suggests that against the delta variant, which is now dominant in UK, two doses of any of the vaccines available in Britain are estimated to offer 79% protection against symptomatic COVID and 96% protection against hospitalisation.
We dont have clear estimates yet from Public Health England on the level of protection against death caused by the delta variant fortunately, this is partly driven by the fact deaths have been relatively low during this third wave in the UK.
But for the alpha variant, Public Health England data estimates the Pfizer vaccine to be between 95% and 99% effective at preventing death from COVID-19, with the AstraZeneca vaccine estimated to be between 75% and 99% effective. The evidence we have so far doesnt suggest that the delta variant substantially changes this picture.
Theres lots we still need to learn about how people with both vaccine doses respond to getting infected with the virus. The UKs COVID Symptom Study is looking at this. One of the key questions that remain is who is at most risk. Emerging data released in a preprint, so yet to be reviewed by other scientists suggests people who are overweight or obese, poorer people, and people with health conditions causing frailty seem to be more likely to get infected after having both jabs.