Immunity against SARS-Coronavirus 2 in breast milk

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) is a positive-sense
single-stranded RNA virus from the Coronaviridae family that is the cause of
coronavirus disease 2019 (COVID-19). The virus was first identified in China in
December 2019 and the outbreak was declared a pandemic by the World Health
Organization (WHO) on 11 March 2020.
At this moment, there are some reports of COVID-19 in infants. Evidence is
emerging that children suffer less severely from COVID-19, however, they do get
infected and spread the virus.In addition, there are some neonates and infants
suffering severely from COVID-19 and need to be hospitalized.
Until now, there is no effective treatment or vaccine available. In general,
maternal milk antibodies may provide additional protection to infants. It is
known that antibodies against influenza are secreted into breast milk (and in
lesser amounts available in donor breast milk) and that they may provide
additional protection to young infants. However, there is not much known about
transmission of antibodies to coronaviruses into human milk. During the SARS in
2002-2004 outbreak, a pregnant woman who got infected at the second trimester
and required mechanical ventilation at the intensive care recovered and
delivered a healthy 38-week infant. After birth, antibodies to SARS-CoV were
detected in maternal serum, cord blood and milk with no evidence of the virus.
So, there is some evidence that antibodies to coronaviruses are secreted in the
breast milk. For SARS-CoV2 infection, this data is missing.
When a mother has been infected with a virus, antibodies are produced against
many epitopes on multiple virus proteins. A subset of these antibodies can
block virus infection by a process that is called neutralization. Viruses,
(such as SARS-CoV2) that infect mucosal surfaces could encounter secretory IgA
antibodies present at the apical surfaces of epithelial cells. Viruses that
spread in the blood will be exposed to IgG, IgA and IgM antibodies directed
against this specific virus. Our aim is to measure the specific antibodies
against SARS-COV 2 in breast milk. If these antibodies are present in breast
milk, even after pasteurization, donor breast milk might be used to support
young infants with a severe COVID-19 infection that need to be hospitalized.
At this moment, there is no evidence that the virus is secreted by the mother*s
milk and COVID-19 positive mothers are encouraged to maintain breast feeding
after practice hand hygiene with a face mask, or by pumping their milk.

1. To evaluate if breastmilk of mothers who recovered from a proven COVID-19
infection contains antibodies (IgA) against SARS-CoV2.
2. To evaluate if these antibodies are still present after pasteurization
according the Holder method.

A prospective observational cohort study in which all participants will undergo
blood sampling for circulating antibody analyses (neutralizing antibodies,
specific IgG, IgA and IgM against SARS-CoV2) and breast milk sampling for
circulating antibody analysis (IgA against SARS-CoV2). For this study 5 ml of
blood will be collected and one portion of breast milk. The breast milk will be
divided into two samples. One sample will be analysed directly and the other
sample will be pasteurized first (Holder pasteurization: 30 minutes at 62,50
C), to examine the effects of pasteurization.

In addition, the following patient characteristics will be collected: age, days
since recovery of clinical symptoms (fever > 37,5 C, cough, tachypnea, dyspnea,
abdominal cramps, diarrhoea, headache, sore throat), days after giving birth,
SARS-CoV2 PCR test results if available.

We expect a low burden and risk from our study. Participants don't have to come
to the hospital. The only risks are pain and bleeding due to the vena
puncture.