As of May 26, 2020, 5,508,904 confirmed cases (145,279 in France) of COVID-19 and 346,508 deaths (28,457 in France) have been reported since December 8, 2019 worldwide. The rapid increase in the number of cases in our territory caused France to pass to level 3 of the epidemic on March 14, 2020.

The natural history of this disease is still poorly understood, particularly in patients infected with HIV, patients considered to be at higher risk for severe forms.

Knowing the seroprevalence in the population of people living with HIV will make it possible to better understand the Covid infection in immunocompromised patients, know the percentage of immunization and the persistence or not of the antibodies over time, specify the protective nature or not of these antibodies detected.

To date, very little data is available in HIV-infected patients with Sars-Cov-2 infection. Only 11 cases of HIV patients with confirmed Sars-Cov-2 infection have been described in the literature. These patients are under 50 years of age, HIV infection with a controlled viral load in 8/11, 2 patients with a severe course requiring administration of tociluzumab, including one patient who died. In addition, the management of these HIV patients is not codified. Some authors have changed antiretroviral therapy to a protease inhibitor such as lopinavir or darunavir because of encouraging results in vitro but debated in patients. This clearly illustrates the disparity of approaches and the lack of data in this patient population.

Knowing the seroprevalence in the population of people living with HIV will allow us to better understand the Covid-19 infection in immunocompromised patients, know the percentage of immunization and the persistence or not of the antibodies over time as well as their unknown neutralizing effect. until now. No data exist on seroprevalence in the HIV population.

Serological tests can detect the immune response to COVID-19 in serum. Studies to date have shown seroconversion typically within two weeks of symptom onset, with notable differences depending on the studies, techniques and epitopes of the antigens chosen to detect the antibodies. A study which showed that the seropositivity rate reached 50% on the 11th day and 100% on the 39th day with a seroconversion time of 11, 12 and 14 days in median for the total antibodies, IgM and IgG.

Diagnosis of SARS-CoV-2 infection is a major public health issue. Serological tests are currently being developed. Enzyme-linked immunosorbent assay, performed on blood samples, can be performed in an automated manner and provide an estimate of the level of circulating antibody.

These serological tests could identify patients who have developed immunity to SARS-CoV-2 and be useful in the collection of epidemiological data related to COVID-19 or to know the serological status of exposed persons.

Nevertheless, SARS-CoV-2 is a new emerging virus and the antibody response (quantitative and qualitative) in COVID-19 patients is largely unknown and that of patients of HIV patients completely unknown to date. The relevance of the use of serological tests in clinical practice will indeed depend on the prior availability of physiopathological and clinical knowledge allowing their interpretation and ensuring adequate indications such as those recently proposed by the Haute Autorité de Santé ((https: //www.has -sante.fr/jcms/p_3182370/fr/premieres-indications-pour-les-tests-serologiques-du-covid-19, # 9268)).

Studies to date have shown seroconversion typically within two weeks of symptom onset, with notable differences depending on the studies, techniques and epitopes of the antigens chosen to detect the antibodies. A study which showed that the seropositivity rate reached 50% on the 11th day and 100% on the 39th day with a seroconversion time of 11, 12 and 14 days in median for the total antibodies, IgM and IgG.

Also, the immune response does not always mean protective immunization against further infection with the same virus. Only so-called neutralizing antibodies can obtain such protection. But the titer of neutralizing antibody needed to provide protection is still unknown for SARS-CoV-2. To date, the target epitopes of neutralizing antibodies have not yet been identified. In addition, data demonstrating protective immunity against COVID-19 induced by antibodies produced against SARS-CoV-2 are currently very limited.

A Chinese study that studied the antibody response in 175 patients with mild forms of COVID-19 found that 30% of them had low neutralizing antibody titer at the end of hospitalization. Differences in the titer of neutralizing antibodies were observed depending on the age of the patients, the oldest (40-59 and 60-85 years) having higher titers than the youngest (15-39 years). The titers remained stable on a control two weeks later (47/175 patients). This study raises the question of the protection of the duration of this protection.

This is why it is essential to characterize in depth the prevalence of Sars-Cov-2 infection in patients infected with HIV, patients considered to be at high risk of severe forms, and the evolution of antibody production according to the evolution of the epidemic and their protective role over time.

To date, no specific treatment or therapeutic strategy has demonstrated its effectiveness for COVID-19. Some antiretrovirals such as lopinavir / ritonavir, with in vitro activity on Sars-Cov-2, have been tested in real life with discordant results. It will be interesting to look at the antiretroviral treatments of patients who have had a Covid compared to those seronegative in serology.

Inclusion Criteria:

• Age greater than or equal to 18 years
• HIV + patient followed at the Pitié-Salpêtrière hospital
• Known HIV infection
• Having been informed about the study and having given oral consent (no opposition)
• Beneficiary or entitled to a social security scheme

Exclusion Criteria:

• Refusal of participation by the patient
• Patient subject to a legal protection measure

This is a retrospective and prospective cohort study of patients infected with HIV to determine the seroprevalence of COVID-19 infection.

This is a monocentric cohort at the Pitié-Salpêtrière hospital.