Vaccination uptake among kids in SG: Flu shots lag behind pneumococcal vax

Not enough children in Singapore are getting vaccinated against influenza, whereas the number of those who are receiving pneumococcal shots has steadily increased over time.

In a study involving 505 preschool children recruited between 2017 and 2018, only 27.5 percent (95 percent confidence interval [CI], 23.8–31.6) had undergone influenza vaccination at some point in the past, with 11.7 percent (95 percent CI, 9.2–14.8) having received a shot within the past 12 months. [PLoS One 2023;18:e0285561]

On the other hand, the uptake of pneumococcal vaccine was 70.8 percent (95 percent CI, 66.6–74.5) overall. The rates were highest among 2-year-old children (76.1 percent) and lowest among 6-year-old children (56.9 percent).

Several factors showed a strong association with vaccine uptake on multivariable logistic regression analyses. Notably, the odds of being vaccinated against influenza were greater among children residing in landed property as opposed to public housing (adjusted odds ratio [aOR], 2.25, 95 percent CI, 1.07–4.67) and among those who had been vs never been hospitalized due to cough (aOR, 1.85, 95 percent CI, 1.00–3.36). In contrast, the odds of having pneumococcal vaccine were low among children who did vs did not live in households with smokers (aOR, 0.55, 95 percent CI, 0.33–0.91).

Of the included children, 53.1 percent were boys and 77.5 percent were of Chinese ethnicity. The percentage of children with asthma, hay fever, wheezing, and egg allergies were 3.2 percent, 2.4 percent, 13.7 percent, and 1.6 percent, respectively. About 12 percent of children had a history of hospitalization due to cough, 63.5 percent were from households residing in public housing, and 23.8 percent lived in a household with adults who smoked.

Misperception hindering protection

“The suboptimal uptake of influenza vaccine in preschool children in Singapore is in agreement with a previous study in which 15 percent of children had been vaccinated against influenza in the preceding 12 months. It is lower than coverage estimates from Taiwan, with reported coverage of 55 percent in children aged 6 months to 3 years,” according to the investigators. [Vaccine 2017;35:6096-6102; Am J Public Health 2018;108:S188-s193]

Local quantitative and qualitative studies shine a spotlight on the common misconceptions about influenza as something that contributes to low influenza vaccine rates in children, they added.

For the most part, parents and healthcare providers think of influenza vaccine as a primary requirement for people who are travelling outside of Singapore. This, according to the investigators, may reflect the commonly held belief that influenza is a ‘winter disease’, despite year-round transmission in tropical settings.  [Vaccine 2020;38:1834-1841; Vaccine 2017;35:6096-6102]

There are also instances where people have confused influenza with colds (and vice versa) and expressed concerns regarding the safety of receiving yearly influenza shots. [Vaccine 2012;30:2448-2452; Z Gesundh Wiss 2022;30:2619-2626]

Finally, primary care physicians tend to recommend influenza vaccination to high-risk groups such as pregnant women, the elderly, and immunocompromised. Because of this, there might be a shortfall in the advice being provided on yearly influenza vaccination for children without any chronic condition or a history of severe respiratory illness, as the investigators pointed out. [BMC Public Health 2012;12:984]

“Currently all vaccines included in the Singapore Childhood Immunisation Schedule are fully subsidized. Before November 2020, doses of influenza and pneumococcal vaccines could be obtained by means of out-of-pocket payment or by one of the national financial schemes to cover the costs, provided eligibility of the child. In our study, which was conducted in years 2017 and 2018, we saw that younger children were more likely to be vaccinated, indicating that over time, more financial support for pneumococcal vaccination led to increased PCV uptake,” the investigators said. [https://immunizationdata.who.int/pages/coverage/pcv.html?CODE=SGP&ANTIGEN=&YEAR=]

Educational messages needed

Despite the presence of several limitations, including a potential recall bias and social desirability bias, the present study underscores the need to understand factors associated with vaccination on an individual vaccine basis and to monitor these routinely to quantify the impact of vaccination policies on vaccine uptake, according to the investigators.

“Earlier policy changes to minimize financial barriers for pneumococcal vaccinations may have helped to improve uptake. However, providing strategic educational messages to parents on the importance of pneumococcal vaccine could help reduce vaccination gaps further,” they pointed out.

“In contrast to pneumococcal vaccine, annual influenza vaccine uptake remains low and is largely reliant on opportunistic recommendations from healthcare providers. Therefore, doctors and nurses should be reminded of their crucial role in communicating the importance of influenza vaccination,” they added.

The investigators called for additional studies to examine whether the recent policy changes to fully subsidize influenza and pneumococcal vaccines result in an increase in uptake.