PORT OF SPAIN, Trinidad (CMC) — The Omicron BA.5 subvariant, discovered here just over a week ago, is responsible for a rapid increase in COVID-19 infections, Chief Medical Officer Dr Roshan Parasram disclosed on Wednesday.

He told a Ministry of Health COVID-19 press conference that as Omicron continues to be the dominant variant of concern in Trinidad and Tobago, the BA.5 subvariant had overtaken the BA.4 and was close to the BA.2 in terms of the number of cases detected.

“BA.2 of the Omicron sublineages remains the dominant for now at 45.5 per cent of the samples that were recently taken. BA.4 was detected prior to BA.5, but only accounts for 9.1 per cent of the recent Omicron samples, and BA.5 seems to be the most infectious of the lot and was detected in 41 per cent of last week’s sample,” he said.

“Note that it (BA.5) was just first detected only a week prior to that, so it seems to be gaining speed and overtaking BA.2 and BA.4 in terms of the national picture and the international picture very quickly.”

Parasram said the Omicron BA.5 subvariant is possibly the most transmissible COVID-19 variant thus far.

It has been detected in almost 90 countries across the globe and has been identified as being responsible for new waves of COVID-19 outbreaks.

Noting that there is no evidence that the BA.5 subvariant results in more severe illness, only more easily transmissible, Parasram said that in Trinidad and Tobago, some of the BA.5 cases are reinfections.

“We haven’t quantified a particular percentage that has been reinfected, but most of the new variants of concern are prone to reinfection. This is why we have stressed on the booster programme and the importance of getting boosted,” the chief medical officer said.

“Another element of people being reinfected, of course, is waning immunity over time, and most of the studies have shown that after a primary series that a booster should be had after six months, and after your first booster, especially for the vulnerable, you go four to six months and then you have a second booster.

“Most studies have suggested that you should get a booster every six months, then a second booster four to six months after that. It may not completely prevent infections, but will prevent severe disease outcomes in terms of morbidity and mortality related to them,” he added.

While BA.5 is classified as an Omicron variant, it has mutations that distinguish it from other Omicron subvariants, such as BA.1 and BA.2. The three key mutations in its spike protein make it both better at infecting our cells and more adept at slipping past immune defences.