PREGCOVAC-19: the follow up of pregnant women who received COVID-19 vaccination in the Dutch national vaccination program

Thus far over 64 million people have been infected with the severe acute
respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide with over 3 million
global deaths, but understanding the effect of SARS-CoV-2 on pregnant women is
still incomplete. Although severe COVID-19 illness is uncommon, pregnant women
are more likely to require intensive care unit stay than same aged nonpregnant
women, predominantly in the third trimester when the diaphragm is moved up from
its prepregnancy position (2). Most effective novel drugs are contraindicated
for pregnant women, considering scarcity of studies on safety data. These
factors suggest that pregnant women are important candidates for preventive
measures, of which vaccination is gold standard (3). Pregnancy is an
immunotolerant state and therefore the immune responses to vaccination in
pregnant women cannot be assumed from that of nonpregnant women. Knowledge on
the immune response after COVID vaccination in pregnant women is an urgent
matter. From other widely used vaccinations in pregnancy, such as influenza and
pertussis, the goal of vaccination in pregnancy is twofold: To protect both
pregnant women and their offspring, for which antibody response and
transplacental antibody transfer are prerequisite. Thus far it is unknown which
trimester of pregnancy offers the best vaccine efficacy in terms of maternal
protection by antibody response and fetal protection by antibody transfer. This
is an important knowledge gap, as recent CDC data indicate that infants aged 0
to 2 months comprise 20% of all COVID-19 hospitalizations among children below
18 years (4). Initially the Dutch society of Obstetrics and Gynecology (NVOG)
advised to vaccinate pregnant women with occupational SARS-CoV-2 exposure and
women at increased risk for severe or critical COVID-19 only. As of April 22
2021, the NVOG changed this advice and currently advocates to vaccinate all
pregnant women. ( Update standpunt *Vaccinatie tegen COVID-19 rondom
zwangerschap en kraambed* | NVOG)

We have defined the following milestones/deliverables for this project:
1. Evaluation of IgG antibody response in pregnant women after participation in
the Dutch national COVID-19 vaccination program.
2. Evaluation of the relation between gestational age at vaccination and
maternal antibody response and trans placental IgG antibody transfer.
3. Registration of obstetric outcomes.

A prospective observational longitudinal cohort study with minimal invasive
blood sampling:
1. Before vaccination
2. Fifteen days after the first and the second vaccination (if applicable in
the Dutch national COVID-19 vaccination program)
3. At birth. Also cord blood will be collected and the obstetric outcome will
be registered.
In total, a maximum of 10 ml blood at four time points and a maximum of 10 ml
of cord blood will be collected.

It concerns a study with pregnant volunteers who have decided to get vaccinated
through the Dutch national COVID-19 vaccination program. The study concerns the
collection of blood and the filling out of questionnaires. There are no
associated risks.