SARS-COV2 Seroprevalence in a Cohort of Perinatally HIV Infected Children and Young Adults From May to December 2020 in Italy

Chiara Casamento Tumeo (  chiara.casamento@opbg.net ) Bambino Gesu Pediatric Hospital: Ospedale Pediatrico Bambino Gesu https://orcid.org/0000-00022035-6886 Nicola Cotugno Ospedale Pediatrico Bambino Gesu Luana Coltella Bambino Gesu Pediatric Hospital: Ospedale Pediatrico Bambino Gesu Stefania Ranno Bambino Gesu Pediatric Hospital: Ospedale Pediatrico Bambino Gesu Livia Piccioni Bambino Gesu Pediatric Hospital: Ospedale Pediatrico Bambino Gesu Giulia Linardos Bambino Gesu Pediatric Hospital: Ospedale Pediatrico Bambino Gesu Luna Colagrossi Bambino Gesu Pediatric Hospital: Ospedale Pediatrico Bambino Gesu Carlo Concato Bambino Gesu Pediatric Hospital: Ospedale Pediatrico Bambino Gesu Carlo Federico Perno Bambino Gesu Pediatric Hospital: Ospedale Pediatrico Bambino Gesu Stefania Bernardi Bambino Gesu Pediatric Hospital: Ospedale Pediatrico Bambino Gesu

Abstract SARS-CoV2 is a new coronavirus which started spreading in December 2019 from Wuhan, China. The seroprevalence of SARS-CoV2 antibodies allows to de ne a better picture of the spread of SARS-CoV2 infection in the population. The duration of SARS-CoV2 antibodies in the healthy population as well as in immunocompromised patients is still a topic of debate. HIV-infected people are at increased risk of developing complications from contracting a viral illness. Furthermore,their ability to develop and maintain an optimal immunological response to any kind of pathogen appears to be reduced.
We analyzed the overall seroprevalence of SARS-CoV2 antibodies in 85 HIV infected-people on ART aged between 5 and 34 years old from May to January 2021. 88,2%of patients were in a good state of viroimmunological control: 23 showed a VL<40cp/ml and 52 had an undetectable VL. When positive for SARS-CoV2 serology, a con rmatory nasopharyngeal swab for PCR assessment and a second serological assay would be performed.
Out of the 85 patients, 5 proved to be positive for SARS-CoV2 antibodies (rate of prevalence 5.8%). In all 5 cases the nasopharyngeal swabs were negative and the second assay for SARS-CoV2 antibodies performed in 4 out of 5 patients a week later was negative as well. The anamnestic recall brought no elements of suspicion for a past infection.
The duration of SARS-CoV2 antibodies after COVID19 disease is still poorly understood in healthy population and additional studies will be needed to de ne the durability of humoral responses in immunocompromised children and in particular in HIV infected children under effective ART. It is still unknown whether ART or their immunological impairment may in part mitigate the pathogenesis of SARS-CoV-2 infection. Also, it will be interesting to analyze the impact of vaccination against SARS-CoV2 in HIV infected patients with a satisfactory virological control.

Introduction
SARS-CoV2 is a new coronavirus which started spreading in December 2019 from Wuhan, China [1]. The impact of the new coronavirus drove growing attention towards the understanding of the immunological process underlying the infection. Speci cally, serology for SARS-CoV2 started being tested not only as a way to establish the diagnosis of infection, but also for an epidemiological purpose.
The seroprevalence of SARS-CoV2 antibodies, in fact, allows to de ne a better picture of the spread of SARS-CoV2 infection in the population, being many people asymptomatic carriers. The rst wave of the pandemics in Italy was considered to be between February and June 2020 [2] [3], the second wave started in October 2020 and lasted until December 2021 [4]. Italy went into lockdown from March 9th to May 3rd [5] [6]. The cases of COVID19 in Italy, assessed via PCR for SARS-CoV2, were 230.555 at the end of the second wave [7] out of a population of 60.416.400 people [8]. The incidence rate of COVID19 cases was 0,3%. The duration of SARS-CoV2 antibodies in the healthy population as well as in immunocompromised patients is still a topic of debate: while some studies support the disappearance of antibodies in the healthy population within three months from the infection [9] [10], other support their persistence for several months [11].
HIV-infected people are at increased risk of developing complications from contracting a viral illness.
Furthermore, their ability to develop and maintain an optimal immunological response to any kind of pathogen appears to be reduced. [12]

Materials And Methods
We analyzed the overall seroprevalence of SARS-CoV2 antibodies in 85 HIV infected-people aged between 5 and 34 years old attending their regular follow-up at Bambino Gesù Children's Hospital in Rome from May to January 2021. All patients were regularly assuming their ART. 33 patients showed a detectable HIV VL (mean 77,21 cp/ml), with a mean CD4 cell count of 759 cells/ml. Speci cally, out of these 33 patients, 23 showed a VL < 40 cp/ml. The remaining 52 patients had an undetectable HIV VL at enrollement. All patients were tested for SARS-CoV2 IgG by DiaSorin's LIAISON ®. 38 patients were tested both during the rst wave (May to August 2020) and second wave (October 2020 to December 2020) of the pandemics. SARS-CoV2 antibodies were considered to be positive over the range of 12 AU/ml. When positive for SARS-CoV2 serology, patients would undergo a nasopharyngeal swab to detect SARS-CoV2 via PCR as well.

Results
Out of the 85 tested patients, 4 proved to be positive for SARS-CoV2 antibodies (IgG) and in 1 was detected a borderline value (12,7 AU/ml) [ Table 1]. 3 of the positive results and the 1 borderline result were obtained during the rst wave of the pandemics, the fourth positive result instead belonged to the second wave monitoring and was previously seronegative in July 2020.
These 5 patients were all regularly taking their ART, one had a detectable VL (< 40 cp/ml) and their CD4 mean cell count was 845,6 cell/ml. These 5 patients were then subjected to a nasopharyngeal swab to assess or exclude via PCR the presence of SARS-CoV2 in their upper respiratory tract and underwent a second serological assay as well to con rm at a second evaluation the presence of SARS-CoV2 antibodies. In all 5 cases, the nasopharyngeal swabs were negative and the second assay for SARS-CoV2 antibodies was negative as well. None of the patients reported symptoms such as fever, cough, myalgia or fatigue. None of the patients disclosed to have had recent contacts with suspect or con rmed cases of SARS-CoV2 infection. The anamnestic recall brought no elements of suspicion for a past SARS-CoV2 infection.
We also report that in our cohort two had documented SARS-CoV2 infection (assessed via nasopharyngeal PCR). Unfortunately, no serological assays are available for these two patients yet. These two patients had mild fever and cough, didn't require hospitalization and the negativization for SARS-CoV2 PCR occurred within 4 weeks. Their VL at the moment of the infection was negative and their CD4 mean cell/count was 690 cells/ml. Out of the 5 patients who tested positive for SARS-CoV2 serology, none showed detectable IgG for SARS-CoV2 at the following assays. HIV infected people are known to have a lesser ability in building and maintaining an optimal immune response compared to non-HIV infected people. This feature varies according to the stage of infection and how early in their life ART was commenced. [12].
Our data show a slight change in terms of SARS-CoV-2 incidence between the 1st and 2nd wave of the pandemics (4,7% during the 1st wave versus 1,17% during the 2nd wave). 3 patients proved to be positive in the rst wave of the pandemics, one proved positive in January 2020. The two SARS-CoV2 infections assessed via nasopharyngeal swab in our cohort occurred in September 2020.

Discussion
Seroprevalence in our study demonstrated that more than 5,8% patients (considering the missing data concerning the two patients who had con rmed COVID19) were at some point in contact with SARS-CoV2 and it' shard to compare this data to the general population's as no major studies of seroprevalence in Italy have been conducted yet. Apparently, none of these patients developed COVID19 and it's uncertain whether this may partially be due to the good viroimmunological control our patients showed or ART. Furthermore, many are the open questions. Were the analysis methods used during the rst and second phase of the pandemics reliable? If so, did HIV patients eventually lose their antibody title due to their inability to maintain the serological response and was this data ampli ed by an insu cient immunological booster given by minimal exposure to the virus? What will the data concerning post-vaccination serology be? Will HIV patients develop and maintain an adequate serological response following the vaccination?

Conclusions
The rate of incidence of seropositive patients in our cohort turned out to be 5,8% in total, but it's hard to compare these data to the general population's as no major studies of seroprevalence in Italy have been conducted yet. We mean to underline that these patients were all regularly taking their ART, attending their regular follow-up and clinic visits, their VL was undetectable, except for one who had a detectable VL (< 40 cp/ml), and their CD4 mean cell count was 845,6 cell/ml. The duration of SARS-CoV2 antibodies after COVID19 disease is still poorly understood in healthy population and additional studies will be needed to de ne the durability of humoral responses in immune compromised children and in particular in HIV infected children under effective ART. Also, it will be interesting to de ne how HIV infected people will respond to SARS-CoV2 vaccination. Finally, the two patients who developed COVID19 had no signi cant complications nor their clinical presentation and management differed from that of another non HIVinfected person, it is still unknown whether ART or their immunological impairment may in part mitigate the pathogenesis of SARS-CoV-2 infection. It's also signi cant to underline that these two patients Informed consent was obtained from all subjects involved in the study.

Ethics approval:
Approval was obtained from the local ethics committee.

Consent for publication:
Consent for publication was obtained from the editorial o ce from our institution.
Availability of data and material: Chiara Casamento Tumeo and Stefania Bernardi detain the published data.
Con icts of Interest: