Infectious diseases

Serious lung infections could be post-vax serotype replacement disease

A leading paediatric respiratory physician has called for enhanced surveillance to determine the impact of the 13-valent pneumococcal vaccine following preliminary data suggesting it might cause an increase in more virulent S. pneumoniae serotypes.

Speaking ahead of the Asian Pacific Society of Respirology (APSR) Congress in Sydney, Professor Adam Jaffe told the limbic the data was consistent with increasing rates of empyema in children.

While it was a rare complication of pneumonia, empyema could lead to lengthy periods in hospital and interventions such as drainage of pleural fluid and surgery.

“It often involves in excess of one week in hospital; sometimes up to six weeks with complications.”

Professor Jaffe, associate director of research at the Sydney Children’s Hospitals Network, said invasive pneumococcal disease such as meningitis and pneumonia had reduced since the 2011 introduction of the pneumococcal vaccine to the National Immunisation Program Schedule.

But there had been a paradoxical rise in empyema.

“We think this is a result of serotype replacement disease. A lot of us carry pneumococcus in our nasopharynx and if you introduce a vaccine that essentially covers those serotypes, it is possible that it creates a milieu for replacement with other serotypes which can cause disease.”

“You might be replacing one problem with another,” he said.

Professor Jaffe said serotype 1 was no longer problem since the introduction of the 13-valent vaccine but a small number of other serotypes not covered in the vaccine were emerging and causing disease.

The vaccine had little effect on serotypes 3 and 19a.

“We could postulate that what we are seeing is maybe an indication of serotype replacement although numbers are small,” he said.

“It might be that what we are doing is creating an environment where serotype 3 is causing major disease.

He said serotype 3 was more likely to invade pleural spaces and appeared to be more virulent than other serotypes.

“That’s why I’m calling for enhanced surveillance. We want that to be standard in Australia.”

He said new molecular techniques such as 16S PCR were much more sensitive for surveillance.

“We’ve shown previously that with standard surveillance versus 16S PCR you get a very different profile. You get a lot of serotype 3 in enhanced surveillance which we would have missed had we done it with the standard national approach.”

“We need that data first and then we can react to it.”

He said vaccines were highly effective but we had to understand the impact of introducing them and monitor its effectiveness.  It was possibly to tweak the immunogenicity of the vaccine against serotype 3 if required.

He added it was possible that some emerging serotypes may be multi-drug resistant.

Already a member?

Login to keep reading.

Email me a login link

© 2023 the limbic