Introduction
The global pandemic of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been affecting many countries worldwide and is still ongoing.1,2 The first case of COVID-19 was reported in December 2019.3 Subsequently, there are increasing numbers of confirmed cases of COVID-19 all over the world as well as in Hong Kong, China and have included pregnant women at all gestations. The pandemic has continued worldwide due to the lack of definitive treatment, failure of infection control measures, and emergence of mutating strains of the virus, as well as vaccination inequity and hesitancy.4
At the early phase of the pandemic, there were many uncertainties toward the infection caused by this novel coronavirus. A cross-sectional survey performed in our unit in 2020 showed high levels of worry and anxiety among pregnant women regarding the risks of SARS-CoV-2 infection during pregnancy, adverse effects on their pregnancy, and vertical transmission. While our results demonstrated deficit knowledge of pregnant women on COVID-19, universal screening during admission to the hospital for delivery was apparently highly acceptable to them.5 Based on our data, we have adjusted our patient education materials accordingly, as well as logistics in the organization of our obstetric services in our unit, including the implementation of universal screening of SARS-CoV-2 among asymptomatic pregnant women upon admission and allowing birthing partner accompanying-labor after the partners have been screened negative.
The development of COVID-19 vaccines was long awaited and expected to critically improve the pandemic situation. The COVID-19 vaccination program in Hong Kong was launched on 26 February 2021. Two types of vaccines are currently available. The first is an inactivated virus vaccine named CoronaVac, Sinovac, which has been available since the beginning of the program. The second is a messenger RNA (mRNA) vaccine named Comirnaty, BioNTech, which was made available since March 10, 2021. At two months of the implementation of the vaccination program, vaccination uptake of at least one dose was just around 15% of the overall population due to various concerns on the safety profile of the new vaccines. Along with public education and promotion, the vaccination uptake has reached 81.8% for at least one dose and approaching 74% for two doses for the whole population in general in Hong Kong at the time of writing.6 Since the beginning of the COVID-19 vaccination program, there has been a debate on whether pregnant women should be vaccinated because of limited data regarding the safety and efficacy. In May 2021, the Hong Kong College of Obstetricians and Gynaecologists issued an interim consensus to publicly support and encourage COVID-19 vaccination in pregnant and lactating women as a preventive measure, stating that pregnant women should be offered the mRNA COVID-19 vaccine at the same time as the rest of the population, based on their age and clinical risk group.7
By the end of year 2021, there were over 10,000 cases of confirmed COVID-19 in Hong Kong with more than 200 deaths since the start of the pandemic.8 In the last quarter of 2021, the local situation has become relatively dormant in the past half year with the majority of confirmed cases all being imported cases. With the availability of the COVID-19 vaccines, pregnant women may have a different perception toward the pandemic. By exploring their latest understanding and concerns on COVID-19 and its vaccines, targeted education and modification of current clinical policies could help improve our response to this persistent public health crisis. This study aimed to evaluate the acceptance of pregnant women with regards to COVID-19 vaccination during pregnancy and to identify any significant changes in their anxiety and knowledge on COVID-19 compared to our previous survey one year ago before vaccines were available. The situation changed drastically again in the recent month with the fifth wave of COVID-19 bringing confirmed cases to record high numbers.
Materials and methods
Ethical approval
The study was approved by the Research Ethics Committee of Kowloon East Cluster, Hospital Authority (KC/KE-21-0148/ER-2). Informed consent from all participants were obtained via a written consent form attached with the questionnaire.
This cross-sectional study was conducted in the antenatal clinics of the United Christian Hospital (UCH) and Tseung Kwan O Hospital (TKOH) in the Kowloon East Cluster of Hong Kong, China. Based on the findings of the first survey, the sample size was calculated as 390 pregnant women with the assumption that 50% of them should be adequately knowledgeable about COVID-19 in pregnancy and a random error of up to 5% with 95% confidence level would be tolerated. The questionnaires were distributed in printed form to a consecutive cohort of the pregnant women when they attended the antenatal follow up in the two obstetric outpatient clinics from August to October 2021. The questionnaire was collected by the attending staff at the end of each consultation, and unfilled or incompletely filled questionnaires were discarded.
The questionnaires were self-administrated and were available in either Chinese or English versions. The first part of the questionnaire collected basic demographic data from the recruited women. The remaining parts comprised of several domains consisting of 34 questions, four of which had multiple parts. The domains included questions on knowledge on COVID-19 and its vaccines in pregnancy as well as attitudes and behaviors of pregnant women and their partners toward COVID-19. The questions were answered in the formats of either binary (Yes/No), three options (Yes/No/unsure), 4-point Likert scale, or choosing the available answers provided as appropriate. The main difference between the current and the last survey was the introduction of questions concerning knowledge and acceptance of COVID-19 vaccines. The answers from the questionnaires were entered into a database by the first principal investigator and verified by at least one other investigator.
Statistical analysis
The SPSS (Windows version 20.0, IBM Corp, Armonk, New York, United States) was used for data entry and analysis. Categorical variables were presented as frequencies and percentages, and the data were analyzed by the Chi-squared test or Fisher’s exact test as appropriate. All statistical tests were two-tailed, and a P value of <0.05 was considered to be statistically significant. The Strengthening the Reporting of Observational Studies in Epidemiology guidelines were followed in the preparation of this article.
Results
The study was introduced to all consecutive pregnant women attending the clinic in the 2-month period from August 16, 2021 to October 15, 2021 with a total number of 887 pregnant women. Among this cohort, 61 women declined to participate in the study, while two were excluded as they were under 18 years old, and eight were excluded as they were unable to read Chinese or English. A total of 816 women (504 from UCH and 312 from TKOH) were included in the final analysis. Results of this study were compared to that of the first study period during July to August 2020 to detect any changes over time and with the introduction of the COVID-19 vaccines.
The women recruited in this survey were mostly Chinese (771/816, 94.5%). The demographics of the women between the first and current survey were similar, except there were more women in the first trimester (203 (24.9%) in 2021 survey vs. 106 (17.0%) in 2020 survey) and second trimester (310 (38.0%) in 2021 survey vs. 221 (35.5%) in 2020 survey) as compared to third trimester (303 (37.1%) in 2021 survey vs. 296 (47.5%) in 2020 survey). Most patients were less than age 35 (521, 63.8%) and had family monthly income less than $40,000 (507, 62.2%). Approximately half of the women were multiparous (419, 51.3%) and had tertiary education level or above (436, 53.4%) (Table 1).
Table 1 -
Basic epidemiological characteristic of the pregnant women in 2020 and 2021 surveys.
| Maternal characteristics |
2021 Survey (n=816), n (%) |
2020 Survey (n=623), n (%) |
χ
2
|
P
|
| Maternal age |
|
|
0.269 |
0.604 |
| <35 years |
521 (63.8) |
406 (65.2) |
|
|
| ≥35 years |
295 (36.2) |
217 (34.8) |
|
|
| Parity |
|
|
0.946 |
0.331 |
| 0 |
397 (48.7) |
287 (46.1) |
|
|
| ≥1 |
419 (51.3) |
336 (53.9) |
|
|
| Ethnicity |
|
|
0.936 |
0.333 |
| Chinese |
771 (94.5) |
581 (93.3) |
|
|
| Non-Chinese |
45 (5.5) |
42 (6.7) |
|
|
| Education level |
|
|
1.908 |
0.167 |
| Non-tertiary |
380 (46.6) |
310 (49.8) |
|
|
| Tertiary or above |
436 (53.4) |
313 (50.2) |
|
|
| Family income |
|
|
5.537 |
0.136 |
| < $20,000 |
203 (24.9) |
178 (28.6) |
|
|
| $20,000 to $40,000 |
304 (37.3) |
245 (39.3) |
|
|
| $40,001 to $60,000 |
159 (19.5) |
103 (16.5) |
|
|
| > $60,000 |
150 (18.4) |
97 (15.6) |
|
|
| Gestation |
|
|
19.922 |
<0.001 |
| <14 weeks |
203 (24.9) |
106 (17.0) |
|
|
| 14–27 weeks |
310 (38.0) |
221 (35.5) |
|
|
| ≥28 weeks |
303 (37.1) |
296 (47.5) |
|
|
Attitude and knowledge on COVID-19 in pregnancy
Pregnant women were in general less worried about COVID-19 in the current survey as compared to the last survey (48.2% vs. 83.1%, P?<?0.001). Most of the participants expected that SARS-CoV-2 infection in pregnancy would be associated with adverse pregnancy outcomes including miscarriage, stillbirth, fetal growth restriction, and preterm delivery (74.4%) and the maternal infection could be transmitted to the fetus during pregnancy (71.2%). Around one-third of women believed that pregnant women were more susceptible to contract SARS-CoV-2 (32.5%) which was fewer than in the first survey (41.9%) (P?<?0.001). Around the same proportion of women believed that COVID-19 would cause a more severe disease with a higher mortality rate in pregnancy (34.8% vs. 32.6%, P=0.378), but significantly more pregnant women in the current survey thought that maternal SARS-CoV-2 infection was associated with possible teratogenicity (34.6%) than in the last survey (21.0%) (P?<?0.001). Only a minority regarded breastfeeding as safe in the presence of maternal SARS-CoV-2 infection (14.0%), while only 11.3% of pregnant women planned not to breastfeed because of the COVID-19 outbreak, both findings being consistent with the last survey (15.2% and 11.6%, respectively). Compared to the previous survey, a consistent proportion of women believed that SARS-CoV-2 infection could be transmitted to the fetus during pregnancy (71.2% vs. 70.5%). However, a significantly smaller proportion of women perceived that cesarean section would be the preferred mode of delivery for pregnant women with COVID-19 (8.6% vs. 23.6%, P?<?0.001), while conflictingly, a higher proportion (37.4% vs. 29.1%) believed that vertical transmission of SARS-CoV-2 infection was possible during vaginal delivery (Table 2).
Table 2 -
Pregnant women’s attitude and knowledge on COVID-19 in 2020 and 2021 surveys.
| Knowledge on COVID-19 |
2021 Survey (n=816), n (%) |
2020 Survey (n=623), n (%) |
χ
2
|
P
|
| Is worried about contracting SARS-CoV-2 during pregnancy (Felt very worried and worried) |
393 (48.2) |
518 (83.1) |
186.137 |
<0.001 |
| Think that pregnant woman is more susceptible to contract SARS-CoV-2 |
265 (32.5) |
261 (41.9) |
13.513 |
<0.001 |
| Think that pregnant woman contracted with SARS-CoV-2 has a more severe disease and with a higher death rate than general populations |
284 (34.8) |
203 (32.6) |
0.777 |
0.378 |
| Think that SARS-CoV-2 infection in pregnancy is associated with pregnancy complications like miscarriages, stillbirths, growth restriction, and preterm birth of the baby |
607 (74.4) |
457 (73.4) |
0.195 |
0.658 |
| Think that maternal SARS-CoV-2 infection of the mother can cause teratogenicity of the baby |
282 (34.6) |
131 (21.0) |
31.611 |
<0.001 |
| Think that maternal SARS-CoV-2 infection can be transmitted to the fetus during pregnancy |
581 (71.2) |
439 (70.5) |
0.093 |
0.761 |
| Think that maternal SARS-CoV-2 infection can be transmitted to the neonate during vaginal delivery |
305 (37.4) |
181 (29.1) |
10.945 |
0.001 |
| Think that pregnant woman contracted with SARS-CoV-2 has to be delivered by cesarean section |
70 (8.6) |
147 (23.6) |
62.213 |
<0.001 |
| Think that pregnant women contracted with SARS-CoV-2 can breastfeed her baby after delivery |
114 (14.0) |
95 (15.2) |
0.465 |
0.495 |
| Plan not for breastfeed because of the COVID-19 outbreak |
92 (11.3) |
72 (11.6) |
0.028 |
0.867 |
COVID-19: Coronavirus disease 2019; SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2.
Knowledge on COVID-19 vaccines in pregnancy
The participants’ knowledge on COVID-19 vaccines in pregnancy was deficit on the whole, with nearly half of them expressing uncertainty because of concerns related to possible inadequate safety data of COVID-19 vaccines on pregnant women (43.9%), the possible increased susceptibility of pregnant women to side effects and complications of these vaccines (43.5%), the safety to the fetus (43.5%), the ability of these vaccines to transfer antibodies to the fetus (49.4%) or the feasibility of coadministering COVID-19 vaccine with other vaccines at the same time (49.4%). Overall, only 26.0% of participants believed that pregnant women could receive COVID-19 vaccination, and almost half of them thought that COVID-19 vaccines had not been formally tested on pregnant women (40.4%), or could be unsafe to the fetus (44.7%). Around a third of women perceived that they were more prone to the side effects and complications of COVID-19 vaccines than the general population (38.2%) and did not recognize that maternal COVID-19 vaccination could effect transferral of antibodies to the fetus to promote postnatal passive immunity (36.2%) (Table 3).
Table 3 -
Pregnant women’s knowledge on COVID-19 vaccine (
n=816).
| Knowledge on COVID-19 vaccine |
Yes, n (%) |
No, n (%) |
Unsure, n (%) |
| Pregnant women can have COVID-19 vaccination |
212 (26.0) |
402 (49.3) |
202 (24.8) |
| COVID-19 vaccines have been formally tested on pregnant patients |
128 (15.7) |
330 (40.4) |
358 (43.9) |
| Pregnant woman is more susceptible to the side effects and complication of COVID-19 vaccine than non-pregnant women |
312 (38.2) |
149 (18.3) |
355 (43.5) |
| COVID-19 vaccine is safe to the fetus |
96 (11.8) |
365 (44.7) |
355 (43.5) |
| COVID-19 vaccine during pregnancy can transfer the antibodies to the fetus and lower the chance of the baby having COVID-19 infection after birth |
118 (14.5) |
295 (36.2) |
403 (49.4) |
| COVID-19 vaccine can be administrated at the same time with other vaccines such as influenza vaccine/pertussis vaccine? |
118 (14.5) |
295 (36.2) |
403 (49.4) |
COVID-19: Coronavirus disease 2019.
Attitudes and behaviors of pregnant women and their partners toward COVID-19 vaccines uptake
Most of the women in the cohort had not been vaccinated (87.6%). While 4.9% of them were vaccinated before pregnancy only 0.5% had received vaccination knowing that they were already pregnant, while another 7.0% of them were vaccinated during pregnancy without knowing they were pregnant at the time. Overall, only 1.7% of them would consider vaccination during pregnancy. They were mainly worried about the safety to the fetus (93.9%) and to themselves (45.5%). For those who would not consider vaccination during pregnancy, almost half of them excused themselves with the reason that her partner or other family members were already vaccinated (45.1%). On the contrary, around two-thirds (67.8%) of the spouses had already been vaccinated (Table 4).
Table 4 -
Pregnant women’s attitude on uptake on COVID-19 vaccine.
| Uptake on COVID-19 vaccine |
Number (%) |
| Pregnant women who already had COVID-19 vaccination (n=816) |
|
| No |
715 (87.6) |
| Yes, already had vaccinated before pregnancy |
40 (4.9) |
| Yes, already had vaccinated during pregnancy but not known she was pregnant at that time |
57 (7.0) |
| Yes, already had vaccinated during pregnancy and known she was pregnant at that time |
4 (0.5) |
| Pregnant women who will consider to vaccination during pregnancy (after excluding those who already had vaccinated, n=715) |
12 (1.7) |
| For those pregnant women who will not consider to have vaccination, the reasons were: (can choose more than one, n=703) |
|
| Worried that the vaccine was unsafe to her |
320 (45.5) |
| Worried that the vaccine was unsafe to her fetus |
660 (93.9) |
| Her husband and other family members were already vaccinated |
317 (45.1) |
| Their partner had already been vaccinated (n=816) |
|
| No |
263 (32.2) |
| Yes |
553 (67.8) |
| Want the hospital to provide more information on COVID-19 vaccination during pregnancy (n=816) |
|
| No |
186 (22.8) |
| Yes |
630 (77.2) |
COVID-19: Coronavirus disease 2019.
A univariate analysis to identify any significant epidemiological factors that could be associated with the women’s intention to be vaccinated during pregnancy showed that non-Chinese women appeared to have less vaccination hesitancy than Chinese women (Table 5).
Table 5 -
Relationship of epidemiological factors and pregnant women’s intention to receive COVID-19 vaccine during
pregnancy.
| Epidemiological factors |
Do not plan to have vaccine during pregnancy (n=703), n (%) |
Plan to have vaccine during pregnancy or already have vaccine during pregnancy* (n=16), n (%) |
χ
2
|
P
|
| Maternal age |
|
|
2.149 |
0.143 |
| <35 years |
446 (63.4) |
13 (81.2) |
|
|
| ≥35 years |
257 (36.6) |
3 (18.8) |
|
|
| Parity |
|
|
2.353 |
0.125 |
| Nulliparous |
347 (49.4) |
11 (68.8) |
|
|
| Multiparous |
356 (50.6) |
5 (31.2) |
|
|
| Ethnicity |
|
|
7.868 |
0.030 |
| Chinese |
674 (95.9) |
13 (81.2) |
|
|
| Non-Chinese |
29 (4.1) |
3 (18.8) |
|
|
| Education level |
|
|
0.629 |
0.428 |
| Non-tertiary |
334 (47.5) |
6 (37.5) |
|
|
| Tertiary or above |
369 (52.5) |
10 (62.5) |
|
|
| Family income |
|
|
0.378 |
0.539 |
| ≤$40,000 |
448 (63.7) |
9 (56.2) |
|
|
| >$40,000 |
255 (36.3) |
7 (43.8) |
|
|
| Gestation |
|
|
1.420 |
0.233 |
| First/second trimester |
412 (58.6) |
7 (43.8) |
|
|
| Third trimester |
291 (41.4) |
9 (56.2) |
|
|
| Occupation |
|
|
0.964 |
1.000 |
| Low risk to contract SARS-CoV-2 |
663 (94.3) |
16 (100.0) |
|
|
| High risk to contract SARS-CoV-2 |
40 (5.7) |
0 (0.0) |
|
|
*Those women who had COVID-19 vaccine before pregnancy or had vaccine when she was not known that she was pregnant was excluded from the analysis
COVID-19: Coronavirus disease 2019; SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2.
Discussion
Our data showed that Hong Kong pregnant women by large still have significant knowledge gap and concerns about COVID-19 vaccines. Nearly half of the participants believe that pregnant women cannot have COVID-19 vaccination (49.3%) and COVID-19 vaccine is harmful to the fetus (44.7%), and an equal number of women reports uncertainty toward all questions regarding the safety or efficacy of the COVID-19 vaccines.
The current study was performed during a relatively stable period of the pandemic when COVID-19 vaccines had been available for several months since earlier in 2021 and there were no local cases reported for months in Hong Kong. When compared to our previous study during July to August 2020, while Hong Kong was being hit by the third wave of the COVID-19 outbreak, it could be seen that there was a significant relief in anxiety levels toward COVID-19 among pregnant women. Fewer pregnant women in the current survey perceived that they were more susceptible to contract SARS-CoV-2 than in the last survey (32.5% vs. 41.9%, P<0.001). Current evidence has also failed to show that there is an increase in susceptibility to SARS-CoV-2 infection during pregnancy.9 The majority of pregnant women with SARS-CoV-2 infection actually remain asymptomatic.10 However, it has been suggested that they may be at higher risk of more severe disease than non-pregnant women in terms of needing intensive care unit admission, particularly when they are infected during the third trimester.11 While the differences in other clinical indices of disease severity such as the need for oxygen therapy and invasive ventilation remain controversial, available data have suggested that the increased admission for intensive care could possibly be due to a lower threshold for admission in view of pregnancy per se rather than due to the disease severity.10,12–14 There have been reported cases of the need for extra-corporeal membrane oxygenation, but the overall incidence of maternal mortality in high resource countries is low, in contrast to the experience with SARS.15–17 So far there are no maternal deaths due to COVID-19 in Hong Kong.
There continue to be certain misconceptions about the effects of COVID-19 on pregnancy. More women are worried about teratogenic effects on the fetus by maternal SARS-CoV-2 infection in this survey as compared to the previous study (34.6% vs. 21.0%, P?<?0.001), which is not supported by current evidence.18 On the other hand, most pregnant women rightly feel that COVID-19 in pregnancy is associated with adverse pregnancy outcomes (74.4%). Recent systematic reviews have shown that there could be increased risks of miscarriage in pregnant women with COVID-19.19,20 There is also emerging evidence suggesting its associated with stillbirths although the overall incidence of this event was rare.21–23 In contrast, there is no evidence demonstrating increased risk for small for gestational age or intrauterine growth restriction.24 Unlike asymptomatic pregnant women with SARS-CoV-2 infection, pregnant women with symptomatic infection have a two-to-three-fold increased risk of preterm birth, most of these preterm deliveries are medically indicated.21,23,25
Most of the pregnant women in the current cohort acknowledged the risks of vertical transmission of SARS-CoV-2 (71.2%), which, has been supported by systematic reviews.26 More pregnant women in the current survey believed that SARS-CoV-2 could be transmitted to the neonate during vaginal delivery as compared to the last study (37.4% vs. 29.1%, P=0.001). While the literature has reported that vertical transmission during vaginal delivery or in the peripartum period is possible, the actual risks appear to be very low.27 The cesarean section rate for pregnant women with COVID-19 has been reported to be 64% worldwide in systematic reviews and even up to 88% from a meta-analysis for studies from China in 2020 with COVID-19 status as the only indication.28,29 Nevertheless, based on currently available data, it remains very doubtful that a cesarean section can reduce intrapartum vertical transmission. Similarly, artificial feeding instead of breastfeeding or separation of infected mother and newborn baby in the early neonatal period is not apparently able to reduce transmission to the neonate.27 There are also no differences demonstrated in terms of neonatal or maternal mortalities between cesarean section and vaginal delivery in COVID-19 confirmed pregnancies.30 The current survey showed that fewer women believed that they had to be delivered by cesarean section if they had contracted SARS-CoV-2 as compared to the previous study (8.6% vs. 23.6%, P?<?0.001). Their responses were in line with direction and evidence from current literature,27,30 and that the mode of delivery should be individualized according to the obstetric indications and disease severity.
Vaccines for COVID-19 has been introduced for almost a year in Hong Kong. CoronaVac has been reported as contraindicated for pregnant or lactating women because of the lack of efficacy and safety data in pregnancy, while Comirnaty is regarded as the choice of COVID-19 vaccine for pregnant women and has a reported efficacy of 95% (95% confidence interval: 90.0%–97.9%) against symptomatic COVID-19.20,31 There has been accumulating evidence on the safety and efficacy of these vaccines that supported the use of COVID-19 in pregnancy.32 The registry of the Center for Disease Control and Prevention of the US has not revealed any risks in safety of using the mRNA COVID-19 vaccines for pregnant or lactating women.33 Pregnant women have not been shown to be more susceptible to the side effects and complications of COVID-19 vaccines than the non-pregnant counterpart. Some observational studies have even suggested pregnant women may experience less systemic side effects such as fever with Comirnaty, and the vaccine is not known to be associated with venous thromboembolism or thrombocytopaenia in pregnancy.34–36 No evidence has indicated that vaccination with Comirnaty during pregnancy is associated with fetal risks such as miscarriage or congenital anomalies.34 So far current evidence is inconsistent and has yet to show any significant differences of the immunogenicity for COVID-19 vaccines among pregnant versus non-pregnant women, so that further ongoing research is needed.37 The latest evidence has suggested the potential benefits of passive immunity of the neonate from placental transferral of anti-SARS-CoV-2 antibodies after vaccination during pregnancy, as these antibodies are detected in cord blood of the newborn and in breast milk after maternal COVID-19 vaccination.38,39 However, whether the presence of these maternally conferred antibodies truly equates passive immunity and the extent of protection to the newborn requires further investigation.
Our study has shown that nearly half of the participants believe that pregnant women cannot have COVID-19 vaccination (49.3%) and COVID-19 vaccine is harmful to the fetus (44.7%). These results clearly demonstrate the need for more focused education on COVID-19 vaccines in pregnancy. Pamphlets and fact sheets on COVID-19 vaccines can be provided to pregnant women during antenatal consultations as a starting point to clarify their misunderstandings and reduce their anxiety and hesitation about these vaccines. Further reinforcement should then be given via videos broadcast at the clinics, and through direct counseling by doctors and midwives during consultation to promote vaccination among pregnant women.
In our study, only 1.7% participants would consider vaccinating during pregnancy, and among the participants who had been vaccinated during pregnancy, the majority of them did not know that they were pregnant at the time of vaccination (93.4%, 57/61). The low uptake of COVID-19 vaccines among pregnant women in Hong Kong, China is consistent with other parts of the world.40 From a cohort study in the United Kingdom between March and July 2021, less than one-third of pregnant women showed acceptance to COVID-19 vaccination during pregnancy, with younger women, non-White ethnicity, and lower socioeconomic background being associated with a lower uptake.41
The importance of household transmission of SARS-CoV-2 has been illustrated by a systematic review and meta-analysis,42 demonstrating that vaccination of members of the same household can lower the risk of being infected and thus reducing the risk of pregnant women contracting SARS-CoV-2. In our study, 67.8% of the participants’ partners were vaccinated, which was similar to the vaccination rate of the overall population in Hong Kong.6 Given the very low vaccine uptake rate in pregnant women, partner vaccination rates should be targeted at even higher levels to achieve the optimal benefits of household vaccination. The concept of household vaccination should be explicitly conveyed to the pregnant women and their families to encourage other family members to be vaccinated.
One of the limitations of this study was the validity reliability of the questionnaires. Despite the lack of formal validation, a small pilot study by face-to-face interview and counter-checking of replies with the pregnant women by the investigators was carried out when the questionnaire was being developed. In addition, our experience with the first survey and the largely consistent results of both surveys supported the reliability and reproducibility of the survey. Another potential limitation would be the generalizability of the results, as the study only recruited pregnant women in our cluster during a two-month period in 2021 and might not be representative of the general obstetric population in Hong Kong. With the current fifth wave of COVID-19 in Hong Kong bringing record high number of confirmed cases, it could be expected that there would be enhanced motivation for pregnant women to be vaccinated and thus their responses to the questionnaire might now be different.
Conclusion
Despite the availability of COVID-19 vaccines and local and international recommendations for pregnant women to be vaccinated, the uptake of COVID-19 vaccines during pregnancy remained extremely low. Efforts should be made to effectively provide information about the safety and benefits of COVID-19 vaccines during pregnancy. With the persistent pandemic since almost two years ago and the current fifth wave of COVID -19 starting around one month ago bringing record high number of confirmed cases daily, there is an urgent need to booster vaccination rates in pregnant women to avoid excessive adverse pregnancy outcomes. Addressing low vaccine uptake rates in pregnant women appears imperative to protect the health of women and their babies in the ongoing pandemic.
Funding
None.
Author Contributions
All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
Concept or design of the study: Li YY, Lok WY, Kong CW, To WWK.
Acquisition of data: Li YY, Lok WY.
Analysis or interpretation of data: Li YY, Kong CW.
Drafting of the manuscript: Li YY, Kong CW, To WWK, Poon LC.
Critical revision for important intellectual content: All authors.
Conflicts of Interest
None.
Editor Note
Liona C. Poon is an Associate Editor of Maternal-Fetal Medicine. The article was subject to the journal’s standard procedures, with peer review handled independently of this editor and her research group.
Data Availability
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
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