An interesting study published by Collier and others in the Journal of the American Medical Association published online May 13th 2021 sought to answer this question.  

Pregnant women are at an increased risk of morbidity and mortality from COVID-19 but have generally been excluded from the phase 3 COVID-19 vaccine trials.  

Data on vaccine safety and immunogenicity in these populations is therefore limited. 

This study enrolled 103 women who had received a COVID-19 vaccine from December 2020 through to March 2021 and 28 women who had confirmed SARS-CoV-2 infection from April 2020 through to March 2021.  

The study enrolled 30 pregnant women, 16 lactating and 57 neither pregnant nor lactating, who had received either Moderna or Pfizer COVID-19 vaccines. It was included 22 pregnant and 6 non-pregnant unvaccinated women with SARS-CoV-2 infection. 

SARS-CoV-2 receptor binding, neutralising and functional non-neutralising antibody responses from pregnant, lactating and non-pregnant women were assessed following vaccination.  

Spike specific T-cell responses were evaluated using various assays.  Humoral and cellular immune responses were determined against the original SARS-CoV-2 strain as well as against the various variants. 

The study enrolled 103 women aged 18 to 45 who had received the COVID-19 mRNA vaccine.  After the second vaccine dose, fever was reported in four pregnant women, 14%, seven lactating women 44% and 27 non-pregnant women 52%. 

Binding, neutralising and functional non-neutralising antibody responses as well as CD4 and CD8 T-cell responses were present in pregnant, lactating and non-pregnant women following vaccination. 

Binding and neutralising antibodies were also observed in infant cord blood and breast milk.  Binding and neutralising antibody titres against the SARS-CoV-2 B117 and B135 variants of concern were reduced but T-cell responses were preserved against these viral variants. 

The study concluded that receipt of a COVID-19 mRNA vaccine was immunogenic in pregnant women, and vaccine elicited antibodies were transported to infant cord blood and breast milk.  

Pregnant and non-pregnant women who were vaccinated developed cross reactive antibody responses and T-cell responses against SARS-CoV-2 variants of concern. 

The detection of binding and neutralising antibodies in infant cord blood suggests sufficient transplacental transfer of maternal antibodies and it can be concluded that maternal COVID-19 vaccination in pregnancy may confer benefits for newborns who may be ineligible for vaccination. 

Vaccination also elicits binding and neutralising antibodies in breast milk and the authors suggest that the timing of vaccination that optimises delivery of breast milk antibodies to neonates should be considered.  

The results of this study complement other studies which demonstrate neutralising antibodies in both cord blood and breast milk, suggests the possibility that new born’s may be protected by maternal vaccination.  

The authors concluded that receipt of a COVID-19 messenger RNA vaccine was immunogenic in pregnant women, and vaccine elicited antibodies were transported into cord blood and breast milk.  

Pregnant and non-pregnant women who were vaccinated developed cross reactivity antibody responses and T-cell responses against SARS-CoV-2 variants of concern. 

The London General Practice, the leading London doctors’ clinic encourages all those eligible for vaccination to accept and be vaccinated. 

The London General Practice commends the Government on its vaccination programme.

Dr Paul Ettlinger
BM, DRCOG, FRCGP, FRIPH, DOccMed

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