When do COVID-19 vaccines start to work, and how do you check it? [WE EXPLAIN]

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More and more Poles are behind the COVID-19 vaccination. 2,7 million people are fully vaccinated. However, the mere administration of the preparation does not mean that we are safe. Resistance to SARS-CoV-2 does not appear overnight. When do COVID-19 vaccines start to work? What is known about acquired immunity after being infected with the coronavirus? And how to check if we are already secured? We explain.

1. Immunity against COVID-19 does not appear immediately after vaccination
2. The minimum time needed to obtain full immunity after the second dose is: for the Pfizer vaccine – 7 days, Moderny – 14 days, AstraZeneki – 15 days
3. With the Johnson & Johnson single-dose COVID-19 vaccine, full immunity appears 28 days after vaccination. The onset of protection was followed on day 14
4. CDC: If you missed the second dose, you are not fully protected. Take all preventive steps until fully grafted out
5. You can find more such stories on the TvoiLokony home page

Vaccination against COVID-19. Immunity doesn’t show up immediately

At least one dose of the COVID-19 vaccine was taken by 8 million 72 thousand. 900 people, and over 2,7 million are fully vaccinated. However, there are voices that among those vaccinated there are people who think that “everything can be done a few days after the second dose”. Unfortunately, this is not the case.

Of course, COVID-19 vaccines are effective in protecting against the disease, and some pre-pandemic behaviors can be reverted after vaccination. However, you need to know that not immediately, because immunity does not appear immediately after taking the preparation. It takes time for the immune system to make antibodies. How much exactly? How long after taking a dose does the vaccine start working and we can feel fully protected? Let’s take a look at the individual preparations.

Four vaccines against COVID-19 are currently available in Poland: Comirnaty (BioNTech / Pfizer), a preparation from Moderna, AstraZeneca vaccine against COVID-19 (these are administered in two doses) and the Johnson & Johnson vaccine (administered in one dose).

COVID-19 vaccines. What is their effectiveness and when do they start working. TALLY

To begin with, let’s recall the effectiveness of individual COVID-19 vaccines:

Comirnaty vaccine (BioNTech / Pfizer). Clinical studies have shown that almost 95% effective in preventing COVID-19 in people without prior infection. After the first dose, the effectiveness of the preparation was estimated at approx. 52%.

Moderna COVID-19 vaccine. In clinical trials, the effectiveness in preventing symptomatic infection in people with no evidence of prior COVID-19 infection was rated at 94,1%.

AstraZeneca COVID-19 vaccine. Initially, the effectiveness of the product was estimated at 79%, new analyzes of US clinical trials indicated that the effectiveness rate of the preparation is 76%.

Johnson & Johnson vaccine (COVID-19 Vaccine Janssen). The overall effectiveness was estimated at 66%. The effectiveness in preventing the severe form of COVID-19 was finally 85,4%.

1. COVID-19 Vaccines. What do we know about them and how do they differ?

How soon after you have the vaccine does your body start making antibodies to SARS-CoV-2? In other words, since when and to what extent are we protected. Details are presented in the table below.

It is worth noting that partial immunity appears after taking the first dose of the two-dose COVID-19 vaccine. Research analyzes suggest that greater resistance to COVID-19 becomes apparent 14 days after vaccination. With AstraZeneki, protection starts approximately three weeks after the first dose. As for the Johnson & Johnson single dose vaccine, the onset of protection was observed from the 14th day after ingestion.

1. What happens between the first and second doses of the COVID-19 vaccine?

Remember that this does not mean that we are fully protected. It is worth remembering the CDC recommendation for people after your first immunization: if less than two weeks have passed since your immunization, or if you missed a second dose, you are not fully protected. Take all preventive steps until fully grafted out. Particular caution is advised in those who have received the first dose of the two-stage vaccine – if they become ill during this time, the second dose may be delayed.

The immunologist Dr. Paweł Grzesiowski, an expert of the Supreme Medical Council on COVID-19, speaks in a similar vein. The expert points out that if a vaccinated person comes into contact with someone infected between the first and second vaccination, there is a risk of infection with SARS-CoV-2. Dr. Grzesiowski also emphasizes that in such cases, the vaccine adopted will most likely alleviate the effects of COVID-19.

COVID-19. Immunity in convalescents. What do we already know?

Due to the constantly growing number of convalescents (we have over 2,4 million of them in Poland), it is worth recalling what we know about the immunity acquired after passing COVID-19. The most important question is how long immunity against the SARS-CoV-2 coronavirus is maintained after the outbreak. Scientists estimate that it takes up to several months. Researchers from Public Health England (PHE) gave a more specific answer. According to the observations they shared in January, it is at least five months. Specialists noted that this fact does not mean that re-infection with the coronavirus is impossible.

1. Breakthrough information on convalescents. Seniors at a disadvantage

More recent studies in Viruses have found that immunity after contracting COVID-19 remains at a high level for up to 11 months. Read more HERE: How long does immunity last after contracting COVID-19? There is good news

Experts also note that in survivors, IgG antibody levels are highly dependent on the clinical course of COVID-19. In the case of asymptomatic or mildly symptomatic infections, the concentration of IgG antibodies may be very low or disappear within the next few weeks after symptoms disappear. – This does not mean, however, that such people have not acquired any immunity – said a few weeks ago the president of the Polish Society of Epidemiologists and Doctors of Infectious Diseases, prof. Robert Flisiak. In the next contact with SARS-CoV-2, these people will be able to produce antibodies again very quickly.

Scientists also do not rule out re-infection of SARS-CoV-2 in convalescents. – The risk will be greater in people who have low levels of antibodies after primary infection, says Prof. Andrzej Fal from the Cardinal Stefan Wyszyński University in Warsaw (studies show, however, that such events are rare). Currently, there are no indications that the reinfection was characterized by a more severe course, requiring hospitalization. Scientists also note that the risk of reinfection may be related to certain mutations in the coronavirus.

How do you know if you are immune to COVID-19 after vaccination?

The only sure way to know if we are immune to COVID-19, and to what extent, is to do a test. While until now such tests were performed mainly by convalescents, now more and more people vaccinated against the coronavirus are interested in it. What test to do after COVID-19 vaccination and when?

As Medicover instructs, “if we want to check the amount of post-vaccination neutralizing antibodies (i.e. those whose task is to neutralize an infectious virus particle), we should perform an appropriate serological test after the period required for a given vaccine to acquire full immunity”. We have presented them in the table above. When selecting the test for immunity to vaccination, the medical center recommends choosing those tests that assess IgG antibodies against the S protein.

We can choose from qualitative, semi-quantitative and quantitative tests. It is optimal to choose quantitative tests – they are highly reliable, and they inform not only about the presence of antibodies, but also about their concentration.

You may be interested in:

1. 18 questions to answer before vaccinating against COVID-19
2. New COVID-19 vaccine. From Brazil
3. Side effects of COVID-19 vaccines [COMPARISON]