The COVID-19 vaccine booster shot given to the elderly in recent weeks has had an immediate impact on the infection rate among those over 80, with the rate more than halving in just over a two-week period.

While the impact of the first doses of the vaccine led to a drop in infections after weeks, the indications are that the booster’s ability to increase immunity is having a quicker impact.

Epidemiologist Neville Calleja told Times of Malta the effect of the booster on the elderly was noticeable “from the following week” after it was administered.

The latest figures on infection rates in the different age groups show that in two weeks, the rate per 100,000 people in the over-80 cohort dropped from a high of 248.97 to just 87.6. Similar drops were also registered in the 65 to 79 group.

The elderly were among the first to get their COVID-19 vaccine back in January.

Optimism about other indicators

The current rate for the age group, published by the European Centre for Disease Prevention and Control, is also the lowest since mid-July. Since then and until last week, the rate had been climbing, a trend the health authorities blamed on waning immunity.

It was too early to comment concretely on the impact the booster might have had on mortality and hospitalisation rates, Calleja said, but in recent days it seemed the two rates had also started to slow down.

“There is always a lag between incidence and mortality in terms of epidemic trend,” Calleja said. There should be a clearer picture of the situation with mortality and hospitalisation rates in a few weeks’ time, he said.

All residents in care homes for the elderly have received their booster dose, while the health authorities are now in the process of vaccinating the immune-compromised and those aged 70 and over.

The booster dose drive among the elderly in care homes had to be brought forward after a spike in cases as a result of what healthcare professionals described as waning immunity. Times of Malta had reported that the rate among people aged 80 and over in Malta was higher compared to the younger age groups for the first time in months.

Meanwhile, the rates for the remaining age groups have remained consistent. The health authorities have yet to say whether booster doses will be administered to the younger groups, although they revealed the country has enough doses to do so if immunity starts waning in other cohorts, as it did with the elderly.