National Reference Center (NRC) for Streptococcus pneumoniae (invasive)

Important message: High number of invasive pneumococcal isolates (December 2022)

Due to the restrictive measures in the context of the COVID-19 pandemic, a significant and sustained reduction in the number of invasive pneumococcal isolates sent to the NRC UZ Leuven was observed for the years 2020 and 2021. While the number of invasive pneumococcal disease (IPD) strains has been more or less normalized since March 2022 (compared to pre-COVID years 2018 and 2019), we have observed an increase in the number of isolates sent to the NRC from October 2022 onwards. For the month of December 2022, an exceptional high number of IPD isolates has been analysed at the NRC UZ Leuven. Over 300 IPD strains have been received at the NRC, which is the highest number of strains ever received during the time period of one month since the start of the surveillance. The serotype distribution and age distribution in December is in line with what has been observed in other months in 2022. The majority of the strains originates from the adult population (>18 years), with 35% of the IPD isolates in December 2022 for patients with an age between 65 and 85 years old. No specific serotype was the cause of the increase on its own, but serotype 3 and 8, which were in previous years also predominant, were most frequently detected (each in 17% of the cases). 

Based on the number of IPD isolates so far received with a sampling date of January 2023, again a high number of strains is to be expected for the current month, with for the first half of January 2023 already over 150 strains received. 

For other countries in Europe with a strong and stable IPD surveillance (such as Germany, the Netherlands and Denmark), the same trends are observed with both for December 2022 and January 2023 high numbers of invasive pneumococcal isolates received. Possibly the intense circulation of different respiratory pathogens (e.g. Influenza, RSV) at the same moment, after lifting most restrictive measures in the context of the SARS-CoV-2 pandemic, may have resulted in the exceptional high incidence of invasive (super)infections with Pneumococci. 

Helpful links:

At the bottom of this page, you can find the NRC reports.

You can consult the accompanying epidemiological surveillance reports at: Health topic Lung inflammation, Health topic Vaccine-preventable diseases. 

The slides from the information session (30/03/2023) regarding the activities of the NRC Streptococcus pneumoniae can be consulted via: Information Session March 2023