The first Specchio-COVID19 Webinar is online!

For those of you who were unable to attend this live event, we wanted to make it possible for you to replay the webinar.

Four scientific investigators from Specchio gave an update on the progress of research and knowledge on COVID-19, before answering the many questions from the participants:

• General presentation of the Specchio-COVID19 studies: Pre Silvia Stringhini, Head of the Population Epidemiology Unit (UEP), HUG/University of Geneva
• Advances in knowledge about long COVID : Professor Idris Guessous, Head of the Department of Primary Care Medicine, HUG/University of Geneva
• Update on the vaccination strategy in the canton of Geneva: Pre Klara Posfay Barbe, Head of General Paediatrics, HUG/University of Geneva
• Update on the pandemic in Switzerland: Prof. Didier Pittet, Head of Infection Prevention and Control, HUG/University of Geneva

The webinar was specifically dedicated to participants in the seroprevalence studies carried out by the Population Epidemiology Unit in the context of the pandemic. The event attracted more than 480 people online for two hours, and we received almost 500 questions.

You can find more answers to your questions in the webinar video.

ANSWERS TO YOUR QUESTIONS

We've grouped our answers into categories, following your most frequently asked questions.

Please note that information changes rapidly over time, in line with advances in research and official public health recommendations. For individual questions of a medical nature or for special cases, we recommend that you contact your GP. Useful links to official websites are provided at the end of this document.

• HERD IMMUNITY

What level of herd immunity is needed to emerge from the health crisis?

It is difficult to define a collective immunity threshold at which we can be sure of emerging from the current pandemic. Initially, scientific calculations showed that a rate of 60 or 70% might be sufficient. Now, with the arrival of new variants, some of which are much more contagious than the first, experts agree that a higher rate of herd immunity is needed, in the region of 80 or 90%. Ideally, the entire population should develop antibodies, so that we can hope to return to a way of life that is not dictated by the health crisis measures in place.

Vaccination enables herd immunity to be achieved. If a high percentage of the population is vaccinated (generally estimated at between 80% and 95%), people who have not been vaccinated can also benefit from protection. With so many people vaccinated, the infectious agent no longer has a sufficient reservoir to multiply and spread.

How up-to-date is the estimated overall seroprevalence of COVID-19 in Geneva, by age group and gender?

In our latest seroprevalence studies (July 2021), data collected from 3,121 people from a representative sample of the Geneva population revealed that, at the time of the pandemic's decline, 67% of the Geneva population as a whole had developed antibodies against SARS-CoV-2.For half of them, the presence of antibodies was linked to natural infection by the virus, while for the other half it was the result of vaccination.

The study highlights significant differences between age groups.Seroprevalence was highest among people aged 65 and over, with over 90% of them immune, and lowest among the under-12s, of whom only one child in three had been in contact with the virus.There was no significant difference between men and women.

Since the last evaluation took place in June, and the vaccination campaign has progressed since then, it is likely that the proportion of people who have developed antibodies against SARS-CoV-2 at the time of writing (October 2021) will be higher than 67%. The exact proportion is difficult to estimate without a new study, and in the absence of a new wave of infections, progress depends almost entirely on the success of the vaccination campaign.

• VACCINATION AND SIDE EFFECTS

What are the long-term side-effects and risks following vaccination?

The mild side-effects after vaccination are similar to those after other vaccines, and are mainly pain around the injection site, fatigue, headaches and fever. The risk of other extremely rare, unusual or serious short-term side-effects following vaccination cannot be ruled out.

To date, the main known serious risk for messenger RNA vaccines administered in Switzerland is that of an allergic reaction, especially in people who have already had a serious allergic reaction to a vaccine or one of its components. More rarely, inflammation of the heart has been observed, more often after the second dose and in young men. These patients were treated and recovered. It is important to note that the risk of inflammation of the heart remains much higher, and the prognosis more severe, following infection with SARS-CoV-2 compared with vaccination. Great care is taken to monitor the side-effects of vaccination.

In all cases, we recommend that if you have any allergies or very specific questions, you speak to your GP.

Can vaccines change our DNA?

The two messenger RNA (mRNA) vaccines currently authorised and used in Switzerland (Moderna and PFizer) cannot alter our genetic material because their mRNA does not penetrate the protected nucleus of the cell where your genetic material (DNA) is enclosed.

Is there a risk of "over-vaccination"?

In response to fears about potential "over-vaccination" linked to repeated doses, it should be noted that this term does not exist in medicine. We are constantly exposed to thousands of viruses. Our bodies are used to being stimulated repeatedly. In the case of COVID-19, it's true that clinical symptoms (such as fatigue, headaches and fever) are sometimes more pronounced after the second dose than after the first, but this doesn't indicate a risk so much as a sign that the immune system has learned to react, which is a good sign.

If there is clinical evidence to support it, it may be advisable to do a booster, stimulating the immune system again for a better response to attacks by this virus and its variants. Other, more traditional vaccines, for which we have significant experience, have never shown any risks associated with an overdose of booster shots.

How do you convince someone who doesn't want to be vaccinated to do so?

Vaccination reduces the risk of being infected with SARS-CoV-2 and of transmitting it. Vaccination helps to protect oneself and others, in particular vulnerable people and people who do not have access to the vaccine (e.g. children). The more people are vaccinated, the less the virus circulates and the fewer people contract it or develop severe forms.

The risk of serious complications from COVID-19 is several times greater than the likelihood of severe side-effects following vaccination against COVID-19.

• SEROLOGICAL TESTS AND VACCINATION

Is there a threshold antibody level above which a person is protected against infection with SARS-CoV-2?

To date, there is no critical threshold of antibody level above which it is certain that a person is protected; it is therefore difficult, if not impossible, to establish a sufficient threshold that would make vaccination unnecessary. What's more, it's important to understand that the immune system tends to become less effective with age (immunosenescence), and that antibody levels and their effectiveness also tend to decline over time.

This is why a booster dose may be necessary to boost immunity. At the time of writing, this booster dose is already recommended in Switzerland for people who are immuno-suppressed or whose immunity is less effective.

Why can't a high level of antibodies prevent people from being vaccinated?

Given the current state of knowledge (October 2021), it is not recommended to systematically carry out a serology test before being vaccinated. This could change in the future as a result of a consolidation of scientific evidence and political considerations (which we do not control).

Furthermore, as far as we know, there is no direct correlation between antibody levels and the level of protection against Sars-CoV-2 infection. We cannot therefore over-interpret the presence of an isolated antibody level, because a cumulative effect of various biological factors interact in the immune response phenomenon. Finally, antibody levels change over time, and protection perceived at one point may no longer be the case a little later.

Why not have a serology test before being vaccinated?

At the time of writing (October 2021), several studies are underway which we hope will provide more scientific evidence on these important issues. We would remind you that in our studies, we focus all our efforts on producing scientific evidence, which is then evaluated and weighed against other factors by the political decision-makers mandated to provide answers in the field of public health.

• VACCINATION, VARIANTS

Do vaccines protect against new variants?

The mRNA vaccines are very effective and offer very high protection after two doses of vaccine, or a single dose for those previously infected with SARS-CoV-2. Vaccinated people are much less likely to be infected than those who are not vaccinated. If infected, they are also less likely to transmit the virus to others. The Pfizer/BioNTech and Moderna vaccines developed to combat the first variant present in 2020 were 95% effective against infection. Efficacy against infection with the new variants appears to be slightly reduced, but efficacy against severe infections requiring hospitalisation remains very high.

According to the Swiss Federal Office of Public Health, it can be assumed that the duration of protection against mild forms of the Delta variant is shorter than that observed for the Alpha variant. Infections may be more frequent before 12 months after vaccination, particularly in older age groups. For the time being, however, there is no indication that vaccination protection against severe forms of the Delta variant is significantly lower or shorter than for the Alpha variant; it probably lasts for at least 12 months.

Compared with unvaccinated people, people who have received the vaccine are significantly less infected with the Delta variant, indicating that the vaccine interrupts the chain of transmission and may reduce the circulation of the virus within the population. Compared with unvaccinated people, vaccination remains effective against infection by the Delta variant and appears to shorten the infectious phase in infected people, thereby reducing transmission of the virus.

However, in rare cases, a vaccinated person may still be contaminated, in which case they could also retransmit the virus. That's why we recommend that, even if you have been vaccinated, you continue to adopt barrier measures (e.g. wearing a mask, keeping your distance from friends and family, hand hygiene).

• CHILDREN, ADOLESCENTS AND PREGNANT WOMEN

Should children be vaccinated?

Vaccination is recommended for adolescents aged 12 and over. The advantages of vaccination are not so much that it prevents severe forms of the infection, which are very rare in this age group, but that it prevents the development of a "long COVID", i.e. symptoms (such as fatigue, exhaustion, etc.) that can last for more than 4 weeks. What's more, since vaccinated people help to reduce transmission of the virus, extending vaccination to younger age groups helps to build herd immunity.

Can children transmit the virus?

Studies show that transmission generally occurs from adults to children rather than vice versa, which is unusual for respiratory viruses. However, a child infected with SARS-CoV-2 can obviously transmit it to those around him, particularly within the family. This is why clusters, particularly those occurring in nurseries and schools, are being closely monitored. The results of our study SEROCoV-Schools study will give us a better understanding of the transmission chains.

What are the recommendations for pregnant or breast-feeding women?

Vaccination with the mRNA vaccines authorised in Switzerland is now recommended for all pregnant women (ideally from the second trimester onwards) and during the breastfeeding period. However, if you have very specific questions, we recommend that you discuss them with your GP, gynaecologist, paediatrician or any other health professional who follows you regularly.

What do we know about the transmission of antibodies from mother to child?

Studies, in particular one at the HUG, are under way in vaccinated pregnant women to find out more about the development of antibodies in the baby and its protection.

• COVID-LONG: CLINICAL ASPECTS AND TREATMENT

What are the clinical signs of long COVID?

Long COVID is based on several criteria: having had at least one positive screening test for COVID (positive PCR test or rapid test or positive serological tests) and symptoms compatible with COVID-19 that persist beyond 4 weeks and have no other apparent medical cause. By collecting data (or 'reporting') from people affected by long COVID, we can improve our knowledge, better identify the symptoms of long COVID and provide better care.

The CoviCare study study, which began more than 12 months ago, has shown that patients (men and women), often young, who have mild symptoms at the time of infection, have persistent symptoms after a first infection with COVID, with disturbed respiratory mechanisms. 7 months after the infection, a quarter of the participants have retained stigmata or after-effects (concentration problems, fatigue, difficulty breathing on exertion, depression).

Who can I turn to if I have clinical signs of long-term COVID or post-COVID symptoms?

The HUG are continually drawing up guidelines to help healthcare professionals manage long-onset COVID. At the HUG, a long COVID consultation (by appointment) has been set up (consultation.longcovid@hcuge.ch / 022 372 96 77).

An interactive digital platform, called RAFAELis an interactive digital platform for exchanging information on the long-term sequelae of SARS-CoV-2. This platform is equipped with a chatbot that provides immediate answers to the most frequently asked questions. If the answer is not found, the question is sent to the relevant team, which then contacts the enquirer.

What are the risk factors for this disease?

Older age (over 50), gender (with more women), the number of severe symptoms at the time of infection and co-morbidities are the main risk factors for developing long-standing COVID. A calculator (https: longcovidcalculateur.com) has been developed by the HUG to find out the risk of developing long-onset COVID according to a number of individual criteria.

How can you protect yourself from developing long COVID?

The best way to protect yourself from developing long-onset COVID is to be vaccinated against SARS-CoV-2 infection.

Is this disease recognised by insurance companies?

Long COVID is not currently recognised by health insurance. An assessment is under way to have the disability insurance (A.I) recognise this disease.

• STATUS OF SPECCHIO-COVID19 STUDIES

Are other serological tests planned as part of the Specchio-COVID19 study?

New serological tests are regularly offered to Specchio-COVID19 participants according to the scientific needs of the study and following a pre-defined protocol. Participants, whether or not they have been vaccinated, if they are selected according to the study criteria, will therefore be able to find out their antibody levels (through infection or vaccination) over time. The aim is also to be able to monitor participants for as long as possible, even after the health crisis, in order to assess several health indicators over time.

Are seroprevalence studies being conducted in other Swiss cantons? Why not conduct a nationwide study?

Other seroprevalence studies are being carried out in Switzerland as part of the national research programme Corona Immunitasprogramme, coordinated by the Swiss School of Public Health (SSPH+), which aims to collect reliable and comparable epidemiological data on a national scale.

What are the initial results of the SEROCoV-Schools study?

The HUG Population Epidemiology Unit is also conducting other studies in relation to COVID-19, in particular the SEROCoV-Schools study study, which aims to describe the dynamics of SARS-CoV-2 virus transmission in crèches and schools in the canton of Geneva, and soon the SEROCoV-KIDS study, which will monitor the impact of the COVID-19 pandemic on the health and development of children and adolescents.

The initial results on the circulation of the virus in schools, following the study of outbreaks, have not yet been finalised, but will be available shortly on the future 'Research' page of the Specchio-COVID19 platform. What we can say for the moment is that children contribute to transmitting the virus in their family households, but to a lesser extent than our hypotheses, unlike known data on other types of virus. At present, we can expect the virus to circulate more widely among children, as they have not yet had access to vaccination. Data on the severity of infections in children remains reassuring.

• RISKS OF INFECTION AND REINFECTION

Are there individual predispositions to the risk of developing a severe form of COVID-19?

COVID-19 is a stress test for existing chronic diseases, meaning that it highlights certain initial unfavourable health conditions to combat disease and aggression. Clinical data has shown that this does not prevent people in very good health from developing a severe form that requires intensive care.

Are there preventive treatments other than vaccination?

There are currently no preventive recommendations. We do know, however, that risk factors such as obesity and hypertension put people at greater risk of developing a severe form of the disease. Nevertheless, being considered 'healthy' is not enough to be protected against the virus. Vaccination therefore remains, by definition, the best way to protect yourself.

Is it possible to become re-infected once you have been vaccinated?

Yes, it is possible to be infected by SARS-CoV-2 a second time, even if you have been vaccinated. People who have been vaccinated have a much lower risk of being infected or re-infected than those who have not been vaccinated. What's more, these people have much less severe forms of the disease. In rare cases, a vaccinated person may still be contaminated, in which case he or she could also pass on the virus.

Why isn't the virus transmitted to all members of a household?

Like other pathogens, in the case of infectious diseases, transmission does not occur in 100% of cases. Some people have a different immunity, which means that they do not catch a disease that is circulating.

For more information:

The Infovac website

The HUG WEBSITE

TheFOPH WEBSITE

The website of the Swiss Society of Gynaecology and Obstetrics (SSGO)

The website of Swiss Paediatrics

The RAFAEL

We would like to take this opportunity to thank you warmly for your valuable involvement and your commitment to helping to advance research into COVID-19.