ObjectiveSynthesise evidence on production of SARS-CoV-2 antibodies in human milk of individuals who had COVID-19, and antibodies’ ability to neutralise SARS-CoV-2 infectivity.DesignA systematic review of studies published from 1 December 2019 to 16 February 2021 without study design restrictions.SettingData were sourced from PubMed, MEDLINE, Embase, CNKI, CINAHL and WHO COVID-19 database. Search was also performed through reviewing references of selected articles, Google Scholar and preprint servers. Studies that tested human milk for antibodies to SARS-CoV-2 were included.PatientsIndividuals with COVID-19 infection and human milk tested for anti-SARS-CoV-2 neutralising antibodies.Main outcome measuresThe presence of neutralising antibodies in milk samples provided by individuals with COVID-19 infection.ResultsIndividual participant data from 161 persons (14 studies) were extracted and re-pooled. Milk from 133 (82.6%) individuals demonstrated the presence of anti-SARS-CoV-2 immunoglobulin A (IgA), IgM and/or IgG. Illness severity data were available in 146 individuals; 5 (3.4%) had severe disease, 128 (87.7%) had mild disease, while 13 (8.9%) were asymptomatic. Presence of neutralising antibodies in milk from 20 (41.7%) of 48 individuals neutralised SARS-CoV-2 infectivity in vitro. Neutralising capacity of antibodies was lost after Holder pasteurisation but preserved after high-pressure pasteurisation.ConclusionHuman milk of lactating individuals after COVID-19 infection contains anti-SARS-CoV-2-specific IgG, IgM and/or IgA, even after mild or asymptomatic infection. Current evidence demonstrates that these antibodies can neutralise SARS-CoV-2 virus in vitro. Holder pasteurisation deactivates SARS-CoV-2-specific IgA, while high-pressure pasteurisation preserves the SARS-CoV-2-specific IgA function.

Objective The mainstay management of hyperphagia and obesity in Prader–Willi syndrome (PWS) relies on dietary restrictions, strict supervision and behavioural modifications, which can be stressful for the patient and caregiver. There is no established pharmacological strategy to manage this aspect of PWS. Theoretically, glucagon‐like peptide‐1 (GLP‐1) receptor agonists (GLP1‐RA) used in patients with obesity and type 2 diabetes mellitus (T2DM) may be efficacious in weight and glycaemic control of PWS patients. We conducted a systematic review of the literature to summarize the evidence on the use of GLP1‐RA in PWS patients. Design Primary studies were searched in major databases using key concepts ‘Prader–Willi syndrome’ and ‘GLP1 receptor agonist’ and outcomes, ‘weight control OR glycaemic control OR appetite regulation’. Results Ten studies included, summarizing GLP1‐RA use in 23 PWS patients (age, 13–37 years), who had used either exenatide (n = 14) or liraglutide (n = 9) over a duration of 14 weeks to 4 years. Sixteen (70%) of these patients had T2DM. Ten patients experienced improvement in body mass index, ranging from 1.5 to 16.0 kg/m2, while improvement in HbA1c was seen in 19 of 23 cases, ranging between 0.3% and 7.5%. All five studies reporting appetite or satiety showed improvement in satiety levels. There were no reported serious side effects. Conclusions GLP1‐RA appears safe in PWS patients and may have potential benefits for weight, glycaemic and appetite control. Nonetheless, we also highlight a significant gap in the literature on the lack of well‐designed studies in this area, which limits the recommendation of GLP1‐RA use in PWS patients at present.