Q: What Are The Hematologic/thrombotic Adverse Events That Have Been Linked To The Johnson & Johnson/janssen And Oxford
A: In post-authorization surveillance of the Johnson & Johnson/Janssen COVID-19 vaccine, a small number of rare thrombotic events cerebral venous sinus thrombosis associated with thrombocytopenia were identified among vaccine recipients based on data reported to VAERS. This led to a brief pause in the use of this vaccine on April 13, 2021 and a review of safety data by CDCs Advisory Committee on Immunization Practices on April 23, 2021. In this review, 15 total cases of thrombosis with thrombocytopenia syndrome were identified, including 12 cases of CVST. All the TTS cases occurred among women, and 13 of 15 were in women aged 18-49 years old. The median age of the case patients was 37 years, and the median interval from vaccination to symptom onset was 8 days . There was one case of CVST with thrombocytopenia in a male during the Phase 3 trial of Ad26.COV2.S .
Does Vaccination Make A Difference To Those Who Have Already Had Covid
There is some evidence that vaccination can sharpen immunity in people who have previously been infected with SARS-CoV-2 and recovered. A letter published in the Lancet in March discussed an experiment in which 51 healthcare workers in London were given a single dose of the Pfizer vaccine. Half of the healthcare workers had previously recovered from covid-19 and it was they who experienced the greatest boost in antibodiesmore than 140-fold from peak pre-vaccine levelsagainst the viruss spike protein.14
When Do The First Covid
Not everyone who gets COVID-19 has symptomsin fact, the World Health Organization says 80% of infections are mild or asymptomatic. Yet those who do may develop fever and chills, a cough, muscle or body aches, fatigue, shortness of breath or difficulty breathing, or a loss of taste or smell. Other people with COVID-19 have reported headache, sore throat, congestion or runny nose, nausea or vomiting, and diarrhea.
The Centers for Disease Control and Prevention says symptoms may appear 2-14 days after exposure to the virus. Yes, thats a pretty large window. But a recent study by US immunologists, published in the Annals of Internal Medicine, narrowed it down. They analyzed more than 180 COVID-19 cases and found that, on average, it takes just over five days for COVID-19 symptoms to hit.
The research team also found that 97% of people who get the virus will develop symptoms within 11 days from the time they are first infected. Any of these symptoms can strike at any time during the course of the illness, from day one to the last days.
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How Food Changes Alcohol Processing
Food changes how your body processes alcohol but not how fast it can do it. When alcohol hits an empty stomach, it will move right through, quickly heading to the small intestine and your bloodstream, says Dr. Wakim-Fleming. Youll feel more intoxicated and may notice stronger toxic effects, such as an upset stomach and a hangover.
On the flip side, food makes the alcohol hang out in the stomach for a while. Your stomach gets time to break down some of the alcohol before it moves into the small intestine, she continues. You can avoid some of alcohols toxic effects, but it wont change how soon you can pass an alcohol test.
When Are We Safe
Experts suggest at least 70 to 75 per cent of the population will have to be immunized to control the spread of the virus.
The effectiveness of these vaccines are only going to be as good as the number of people who get them, Vinh said.
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In the early stages, Canada, like the U.S., is focusing on high-risk groups, including long-term care workers and residents, those aged above 80, front-line health care workers, and Indigenous community members.
Dr. Anna Banerji, an infectious disease specialist at the University of Toronto, said this prioritization can help in a significant drop in the number of hospitalizations and deaths.
What we need is for most of the people to get vaccinated so that the outbreak goes down and we get herd immunity, she told Global News.
You want to first vaccinate the people at highest risk of severe disease or death.
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What Is ‘viral Persistence’ And How Does That Affect The Course Of The Disease
Sometimes the coronavirus sticks around longer than expectedand scientists are still trying to figure out why that happens in some patients, how it varies by individual, and exactly how long the virus stays alive inside the body. This is known as viral persistence, and it affects how long someone is contagious and therefore how long they should stay in isolation.
What Is Astrazenecas Vaccine Again
AstraZenecas COVID vaccine is an adenovirus vector vaccine.
This means it uses an adenovirus a common type of virus that affects humans and many other animals. The adenovirus is genetically modified so it doesnt replicate.
Its used as a way to deliver the vaccines information into our cells.
In this case, the information packaged in the adenovirus tells our body how to make the coronavirus spike protein. This teaches our immune system how to deal with the coronavirus if were exposed.
Adenovirus vectors have been used in medicine for a few decades in other vaccines and also cancer therapy. Theyre very good at stimulating both antibody production and T cell responses.
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If True We Can Learn From This
This isnt about which vaccine is better, or picking and choosing which vaccine to get.
Both are excellent vaccines that have saved many, many lives already. We shouldnt play a tribal game where we say were only going to get one type of vaccine.
Its important to learn from both types of vaccine, while we continue to learn about immunity to COVID, so we can incorporate the best characteristics of both into next-generation vaccines that help us better fight COVID and future pandemics.
Im sure mRNA vaccine producers will learn from this and develop new formulas to give a longer-lasting response.
Its worth remembering Pfizer and Modernas vaccines are the first mRNA vaccines ever approved for use in humans.
There was an immediate need to get antibodies against COVID in our bodies as soon as possible, and theyve done a fantastic job doing that.
What Are The Side Effects Associated With Covid
More than 10 million people have gotten at least one dose of their coronavirus vaccine, according to the Centers for Disease Control and Prevention tracker. The vast majority who talked about their COVID-19 vaccine side effects or reactions described them as similar to a flu shot.
The most common side effects are a sore arm and sometimes fever, chills, tiredness and headaches for a day or two, according to the CDC. As reported in both studies, the majority of reactions beyond a sore arm happen after the second dose. Those are all signs your body is building an immune response. Read more: COVID-19 vaccine clinical trial volunteers talk about living with the vaccine since August
In a study released in January, the CDC said the risk of anaphylaxis a severe allergic reaction is extremely low. Based on data from people who have received the first of the two recommended doses, only about one in every 90,000 people will experience this adverse reaction. The people most at risk of an adverse reaction are those who have had severe allergic reactions to other medications or food. There have been no deaths. On the other hand, the COVID-19 pandemic has killed more than one out of every 1,000 Americans.
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Q: Are The Mrna Vaccines More Efficacious Than The Viral Vector Vaccines
A: None of the COVID-19 vaccines have been directly compared head-to-head in the same population, and so the point estimates of vaccine efficacy for the mRNA vaccines and viral vector vaccines cannot be directly compared with each other. The clinical trials for these vaccines were conducted at different times in different populations. Furthermore, the outcomes used to calculate the efficacy estimates differed between the studies . The Pfizer-BioNTech, Moderna and Johnson & Johnson/Janssen vaccines have all been evaluated for emergency use authorization and met the efficacy criteria pre-specified by the FDA. They all have high efficacy, especially against severe COVID-19.
The Immune Systemthe Bodys Defense Against Infection
To understand how vaccines work, it helps to first look at how the body fights illness. When germs, such as bacteria or viruses, invade the body, they attack and multiply. This invasion, called an infection, is what causes illness. The immune system uses several tools to fight infection. Blood contains red blood cells, for carrying oxygen to tissues and organs, and white or immune cells, for fighting infection. These white cells consist primarily of macrophages, B-lymphocytes and T-lymphocytes:
Vaccines prevent diseases that can be dangerous, or even deadly. Vaccines greatly reduce the risk of infection by working with the bodys natural defenses to safely develop immunity to disease. This fact sheet explains how the body fights infection and how vaccines work to protect people by producing immunity.
- Macrophagesmedia icon are white blood cells that swallow up and digest germs, plus dead or dying cells. The macrophages leave behind parts of the invading germs called antigens. The body identifies antigens as dangerous and stimulates antibodies to attack them.
- B-lymphocytes are defensive white blood cells. They produce antibodies that attack the antigens left behind by the macrophages.
- T-lymphocytes are another type of defensive white blood cell. They attack cells in the body that have already been infected.
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Factors In Flu Shot Effectiveness
Influenza viruses are constantly changing and evolving rapidly. Circulating influenza viruses can mutate from one season to the next.
Researchers need to select the specific influenza viruses to include in the vaccine many months before flu season begins. This means whats in the vaccine may not always match whats actually circulating during flu season. This can decrease the effectiveness of the seasonal flu vaccine.
Age can also play a role in vaccine efficacy because your immune system tends to become weaker as you age. The Food and Drug Administration has approved a high-dose flu vaccine for people 65 and older.
The higher dose is aimed at providing a better immune response and therefore better protection within this age group. for those over 65 with the high-dose vaccine.
The CDC also recommends that some children between the ages of 6 months and 8 years receive two doses of the influenza vaccine during the first season in which theyre vaccinated in order to have sufficient protection.
Its still possible to get the flu after being vaccinated, but research has shown that the illness may be less severe and that people who receive a flu shot may be less likely to be admitted to the hospital if they get the flu.
Q: What Are The Frequency And Characteristics Of Anaphylaxis Or Serious Allergic Reactions After Mrna Covid
A: Anaphylaxis and serious allergic reactions were not observed in the clinical trials of mRNA COVID-19 vaccines, but were recognized shortly after they were authorized for use and deployed in mass vaccination campaigns.
In two separate analyses of data submitted to the Vaccine Adverse Events Reporting System, which comprised reports from 1,893,360 first doses of the Pfizer-BioNTech COVID-19 vaccine and 4,041,396 first doses of the Moderna COVID-19 vaccine in the U.S., there were just 175 cases of possible allergic reactions after the Pfizer-BioNTech vaccine and just 108 cases of possible allergic reactions after the Moderna vaccine.
Finally, in a prospective study of 64,900 Mass General Brigham employees who received a first dose of a mRNA COVID-19 vaccine between Dec. 16, 2020 and Feb. 12, 2021, 1,365 of employees reported any allergic symptoms, and there were 16 employees that experienced of anaphylaxis. Rates of allergic reactions were slightly higher with the Moderna COVID-19 vaccine . Nearly all of the cases of anaphylaxis were among women, and nearly a third had a history of anaphylaxis. One of the cases of anaphylaxis required ICU admission, 9 received IM epinephrine and all recovered without sequelae . CDC has developed recommendations for management of individuals with a history of anaphylaxis or other allergic reactions to the specific ingredients contained within the COVID-19 vaccines or to other substances.
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Q: What Do We Know About The Ability Of The Covid
A: The primary efficacy endpoints of all the COVID-19 vaccine trials were clinical disease however, all of the studies collected data that provide some insight on the ability of these vaccines to prevent asymptomatic infection, including surveillance nasopharyngeal swabs for SARS-CoV-2 viral testing and/or serologies. Since baseline serostatus was known in all these studies, if a subject converted from negative to positive serology during the trial in the absence of a COVID-19 illness, it would imply asymptomatic infection. Some of the vaccines have additionally been evaluated in post-authorization studies in various settings where they have been deployed. Below is a summary of what is known about the impact of each vaccine on asymptomatic infection note that these studies were conducted prior to the emergence of novel variants of concern, including Delta, and these findings may not be generalizable to all variants whose viral kinetics may be substantially different from ancestral strains of SARS-CoV-2:
Pfizer-BioNTech Multiple post-authorization observational studies of BNT162b2 in diverse settings suggest that this vaccine is effective against asymptomatic infection.
United Kingdom: An analysis of new SARS-CoV-2 infections among U.K. health care workers following a mass vaccination campaign with BNT162b2 identified 51 asymptomatic cases among unvaccinated individuals compared with only 10 in the vaccinated cohort .
Can A Vaccine Prevent The Spread Of Coronavirus
Vaccines are typically designed to prevent people from getting sick with the virus, but it is not yet clear if the COVID-19 vaccines by Pfizer or Moderna can stop you from transmitting the virus to others.
This is why is it important for people to continue taking precautions physical distancing, wearing masks and avoiding gatherings, especially in poorly-ventilated spaces until the vaccine is rolled out on a large enough scale so that we know its impact on both infection and transmission, Vinh said.
As experience with past vaccinations has shown, he added, the more people are immunized, the better the chances of reaching herd immunity
According to the World Health Organization , herd immunity is when a population can be protected from a certain virus, like COVID-19, if a threshold of vaccination is reached. Its achieved by protecting people from a virus, not by exposing them to it, the WHO said.
What weve seen with the rollout of the flu vaccines for the last several decades is that it also decreases transmission in the community so that even people who cannot get vaccinated they can still be protected because other people in the community are vaccinated, Vinh said.
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What Are T Cells
Antibodies bind tightly to a specific target, locking onto invading viruses and preventing them from entering our cells.
But the immune system is more than just antibodies.
T cells are also really important for our immune response, and have different roles. One type, known as killer T cells, attack and destroy virus-infected cells.
Another type, known as helper T cells, interpret the nature of the infection and help the immune system respond appropriately. This includes activating killer T cells to destroy virus-infected cells, and also helping B cells make antibodies.
Antibodies wane over time, which can lead to more breakthrough infections in fully vaccinated people.
When viruses are not stopped by antibodies, we rely on killer T cells to eradicate the virus. And T cells almost certainly help prevent severe outcomes if you get COVID.
Its a lot harder for a virus to escape a T cell-based immune response. So a vaccine that generates strong T cell immunity should help retain effectiveness over time against variants including Delta and Omicron.
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All COVID vaccines stimulate our bodies to produce both antibodies and T cells.
Unfortunately, there are not enough data yet to answer these conclusively.
There are many reasons why hospitalisation rates can vary between countries, so its difficult to know how much of a factor the use of AstraZenecas vaccine would be.
Do We Need A Certain Level Of Covid
Dr. Finstad: We dont know that level yet. But given the evidence so far, public health experts are suggesting booster shots for the COVID-19 vaccines. This guidance is awaiting authorization from CDC and FDA.
More research is needed to determine what level of COVID-19 antibodies is protective, and this is an active area of investigation within SeroNet. For measles, for example, antibody testing is used as a surrogate measure to determine whether you’re protected from a future infectionits called a correlate of protection. If you are above that antibody level, you’re likely protected. And vice versaif you fall below that level, your physician will likely give you a booster to raise your antibody levels again.
By following individuals over time through SeroNet studies, we’ll be able to take a look at the antibody levels that correlate with protection. For COVID-19 vaccines, protection means you are protected from developing severe disease, but it doesnt mean you cant get infected. One SeroNet group actually wrote a very helpful article that explains how the vaccines can protect against illness but dont completely prevent you from getting infected.
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