National Serological Monitoring

In order to find out and monitor the level of protection of the population against COVID-19, the Prince's Government has been offering free serological monitoring, since Tuesday 29 June 2021, to people living in the Principality of Monaco. 

In order to find out and monitor the level of protection of the population against COVID-19, the Prince's Government has been offering free serological monitoring, since Tuesday 29 June 2021, to people living in the Principality of Monaco. 

The national serological monitoring programme

The Prince's Government has initiated this national programme, which is designed to keep you informed of your level of protection against COVID-19 on a regular basis.

By taking a simple blood test, you will be able to find out your level of protection against COVID-19, by measuring neutralising antibodies.

This programme is open to anyone who resides in the Principality of Monaco, regardless of age, who meets at least one of the following conditions:

• Has been infected with SARS-CoV-2,
• Has been vaccinated against SARS-CoV-2.

What antibodies are measured?

Neutralising antibodies

Following infection with the severe acute respiratory syndrome Type 2 Coronavirus (SARS-CoV-2), or vaccination against SARS-CoV-2, the body secretes antibodies called "neutralising antibodies."  These antibodies prevent the virus from infecting the cells in your body.

The presence of neutralising antibodies is associated with a decrease in severe forms of COVID-19, and is a marker of immune protection [1][2].  However, there is uncertainty about the duration of protection conferred by vaccination against SARS-CoV-2 or by infection. The latest scientific publications suggest a duration of approximately six to eight months, but this duration varies from individual to individual [3].

Finally, measuring neutralising antibodies can be used as a guide to vaccination: in people who were vaccinated more than six months ago, it is possible that the antibodies have decreased, enabling the virus to cause infections, even leading to severe symptoms [4]. A low level of neutralising antibodies more than six months after vaccination is an indicator for an additional dose of vaccine [5].

How are your neutralising antibodies interpreted?

Neutralising antibodies <30%: An indication for a new dose of vaccine and monitoring of neutralising antibodies three to four weeks later.

Neutralising antibodies between 30% and 60%: in this case, the administration of a new dose of vaccine is left to the discretion of the attending physician and the person concerned.

• If a vaccine is administered, the neutralising antibodies are checked three to four weeks later.
• If no vaccine is administered, the neutralising antibodies are checked three months later.

Neutralising antibodies >60%: There is no need to administer a vaccine; repeat neutralising antibody test six months later.

Anti-S "neutralising" antibodies:  markers of protection following a previous infection with SARS-CoV-2 infection or following vaccination against SARS-CoV-2

Anti-S binding antibodies

We will also measure the so-called anti-S "binding" antibodies, which are directed against the "Spike" protein of the virus. In contrast to the "neutralising" anti-S antibodies, the anti-S "binding" antibodies do not prevent the virus from entering the cells of your body and are not an indicator of protection against COVID-19. These anti-S binding antibodies are simply a marker of your body's natural response to  vaccination against or past infection with COVID-19.

Anti-S "binding" antibodies:  markers of past infection with SARS-CoV-2 or a natural response to the vaccine, without indicating protection

Anti-N binding antibodies

This serological monitoring programme will finally allow you to be aware of the concentration of your anti-N binding antibodies, which are directed against the nucleocapsid of the virus. These antibodies are not an indicator of protection against COVID-19, and simply indicate whether you have been infected with SARS-CoV-2 in the past.

Anti-N "binding" antibodies:  markers of past SARS-CoV-2 infection

The various immunological profiles

Only the presence of neutralising antibodies can confirm protection.

Possible immunological profiles

What monitoring is recommended?

Have you already been vaccinated?

It is recommended that you have a blood test every six months. We will then inform you of your level of protection against COVID-19; your reaction to the vaccine;  and any recent infection with COVID-19, even in the absence of symptoms.

We will ask you about your health, as well as your tolerance of the vaccine (whether you have had any local or systemic side effects).

Have you been infected with SARS-CoV-2?

It is recommended that you have a blood test every six months. We will then inform you of your level of protection against COVID-19 and of any recent infection with COVID-19, even if you have no symptoms.

We will ask you for information about your health.

You will receive the results of these tests within 48 hours.

Will my medical information be kept confidential?

Your health information will be used by the Prince's Government for the purposes of this programme in order to communicate your results to you. It will remain confidential and will be processed anonymously, with the aim of ensuring the good health of the population in the Principality of Monaco.

What is the procedure for taking part in serological monitoring?

The Ministry of Health and Social Affairs has entrusted the Department of Health Affairs with the rollout of this public health programme. Anyone who has previously been vaccinated or has been infected with COVID-19 and wishes to know their level of protection against COVID-19 can phone 92.05.55.00 to be called back for an appointment.

In support of this public health programme, an observational clinical research study, entitled MonaVacc, will make it possible to use the results for statistical purposes, to find out the level of protection of the population and support the public authorities in implementing preventive measures. Individuals will be asked to sign a consent form allowing researchers to use the test results anonymously.

With this public health programme, the Prince's Government aims to consolidate the results obtained so far in the fight against COVID-19.

Didier Gamerdinger, Minister of Health and Social Affairs, stated, "This is an innovative, benevolent approach, which makes it possible to determine the level of protection for the population. We wish to have a long-term view."

Serological monitoring – Full information.pdf

[1] Lucas, C., Klein, J., Sundaram, M.E. et al. Delayed production of neutralizing antibodies correlates with fatal COVID-19. Nat Med 27, 1178–1186 (2021).

[2] Khoury, D.S., Cromer, D., Reynaldi, A. et al. Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection. Nat Med 27, 1205–1211 (2021).

[3] Dispinseri, S., Secchi, M., Pirillo, M.F. et al. Neutralizing antibody responses to SARS-CoV-2 in symptomatic COVID-19 is persistent and critical for survival. Nat Commun 12, 2670 (2021).

[4] COVID, CDC. "Vaccine breakthrough case investigation and reporting. Atlanta, GA: US Department of Health and Human Services, CDC: 2021." (19).

[5] Bergwerk, Moriah, et al. "Covid-19 Breakthrough Infections in Vaccinated Health Care Workers." New England Journal of Medicine (2021).