Pregnant Women Without A Usual Source of Care Show Low Probability of Flu Vaccination

Data show the weighted influenza vaccination rate among pregnant women was 54.5%, with one third not having a usual source of care.

Although both pregnant women and infants ≤6 months of age have a higher risk of complications from influenza, vaccination rates remain low in pregnant women despite recommendations to decrease risk of infection and hospitalization.

Accordingly, a recent study aimed to estimate the prevalence of seasonal influenza vaccination among pregnant women between 2012 - 2016, as well as examine the association between having a usual source of care and vaccination rates in the same population.

A team of investigators, led by Jennifer M. Toth, PharmD, Department of Pharmacy Administration, University of Mississippi, observed pregnant women without a usual source of care had a 24% lower probability of being vaccinated against influenza compared to those with a usual source of care.


They performed a retrospective study using pooled data from the 2012 - 2016 Medical Expenditure Panel Survey (MEPS) Household Component Full-Year Consolidated files and Medical Condition files. The MEPS is a set of large-scale surveys of noninstitutionalized US residents, with panel members completing 5 in-person interviews (rounds) over a 2-year period.

Included patients were pregnant women ≥18 years in the MEPS data between 2012 - 2016 asked the question about having a usual source of care. This data included a pregnancy indicator in rounds 3 and 5 of data collection, specifying whether any female household member was pregnant during that round.

The outcome of interest was the reception of a seasonal influenza vaccine prior to the survey, within the past year. All others were classified as not being vaccinated. This was measured as a binary variable using MEPS data from rounds 3 and 5.

In comparison, the key independent variable for the study was a usual source of care variable from MEPS, collected in rounds 2 and 4 by asking responsendent if there is a particular doctor’s office, clinic, health center, or a place they usually go when sick or need advice about health.

They used a multivariable log-binomial regression model to examine associations between a usual source of care and seasonal influenza vaccination rates.


A total of 1,756 pregnant women were included in the analysis, with a weighted influenza vaccination rate among pregnant women of 54.5% in the past year from the study.

Data show around one-third of patients (30.0%, n = 936,349) of the study population did not have usual sources of care.

Investigators found pregnant women with a usual source of care had an unweighted seasonal influenza vaccination rate of 56.1% compared to 41.8% of those without a usual source of care (weighted 58.5%; 95% CI, 54.3% - 62.6% versus 45.1%; 95% CI, 39.2% - 51.0%).

Additionally, the adjusted prevalence ratio (adjPR) of receiving a seasonal influenza vaccine for pregnant women without a usual source of care was 0.76 (95% CI, 0.60 - 0.98, P = .03).

They found the top 5 main reasons for not having a usual source of care were being seldom or never sick (55.7%), not having health insurance (10.6%), and having recently moved to an area (9.9%).

Then, to confirm the finding that 70% of pregnant women had a usual source of care, investigators estimated the prevalence of having a usual course of care provider in the general population of 18 - 44 years old in MEPS. They found it to be significantly lower at 63%.


“Having a usual health care provider can be important to reassure pregnant women of the safety and efficacy of seasonal influenza vaccination and to make appropriate recommendations,” investigators wrote.

The study, “Association Between A Usual Source Of Care and Influenza Vaccination Rates Among Pregnant Women,” was published in Pharmacoepidemiology & Drug Safety.