Statistics from Northern Ireland's Public Health Agency (PHA) indicate that up to the end of November, uptake of free influenza vaccines was down across all age groups, with nearly half of pensioners not receiving the vaccines by the start of December, reported the Belfast Telegraph.

According to the news source, the over-65s category saw the biggest decline, from nearly 67 percent in 2017 to 52 percent this year.

This age group includes those who were eligible for the new, more effective Fluad vaccine, which has been dogged by complaints about delays to supplies, the news source said.

The PHA has previously needed to make repeated assurances that the final batch of Fluad doses, which had been subject to a phased delivery in three batches due to "manufacturing constraints," would arrive this month, the news source added.

The statistics, which are provided only in percentages from data collected from 325 doctors' practices, show the number of pregnant women who availed themselves of the free vaccine has also fallen to 43.5 percent, down from nearly 47 percent.

Meanwhile, uptake in the 65 and lower at-risk category has dropped from 48.2 percent to 41.7 percent, for toddlers between two and four it has dropped from almost 50 percent to nearly 42 percent. Primary school-aged children also witnessed a slight decrease, from 75.3 percent to 75.1 percent, the figures show.