Invasive pneumococcal disease among children during the COVID-19 pandemic in England

By Shanet Susan AlexReviewed by Danielle Ellis, B.Sc.Jul 14 2022

In a recent article posted to the Emerging Infectious Diseases, researchers demonstrated heightened invasive pneumococcal disease (IPD) incidence in children younger than 15 during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in England.

Background

There was a significant decrease in respiratory infections, particularly IPD, due to the CoV disease 2019 (COVID-19) pandemic and its corresponding lockdowns, social isolation, and other preventative interventions in England. IPD incidences in England decreased by 30% following the initial COVID-19 lockdown in March 2020. The IPD cases stayed low throughout the subsequent winter till February 2021, when they rose by 8% above the three-year pre-pandemic mean incidence for February.

When the nation ended its third nationwide lockdown in March 2021, following the appearance of the SARS-CoV-2 Alpha variant, IPD instances began to rise progressively. There were 25% fewer cases than before the pandemic by June 2021. However, there had been a correspondingly higher rise in cases across children younger than 15.

About the study

The present study examined IPD patterns from July to December 2021, following the removal of all SARS-CoV-2 control measures in England on 19 July 2021. Using national improved surveillance data for England, the researchers compared IPD instances from July through December 2021 to July through December 2020 and July through December in three pre-pandemic years, i.e., 2017 through 2019.

In short, National Health Service (NHS) hospitals routinely send invasive pneumococcal isolates for serotyping and electronic notification of infections to the United Kingdom Health Security Agency (UKHSA). The UKHSA forwards general practitioners a questionnaire about clinical traits, risk variables, patient outcomes, and vaccination background for validated cases. The team employed mid-year population projections from the Office of National Statistics as denominators to compute incidence, utilizing 2020 statistics for 2021 since 2021 data were unavailable.

Results and conclusions

The study results depicted that between July and December of 2021, 1,632 IPD incidents were reported to UKHSA, relative to an average of 2,403 in that same period in the three pre-pandemic years, 2017 through 2019. IPD incidence per 100,000 children fell by 50% among children aged below 15 between July and December 2020. Nevertheless, it rose gradually again in February 2021 and stayed above the average of 145 instances from the three years before the pandemic in July to December 2021.

Case rates increased more quickly in younger age groups, where incidence was highest throughout this timeframe: 10.63 among infants under 1 year; 3.22 among children aged 1 to 4; 1.02 among children aged 5 to 9; and 0.44 among children aged 10 to 14. Incidence from July to December 2021 was lower than the pre-pandemic average from July to December 2017 to 2019 despite an increase in cases among those older than 15 years between February and December 2021.

The age distribution of childhood IPD incidents was similar to that of the pre-pandemic timeframe: 32% of infections were among infants under 1 year old, 42.5 % among children aged 1 to 4, 18 % among children aged 5 to 9, and 7.5 % among children aged 10 to 14. The team found no variation in serotype distribution among years or within age groups in the 172, i.e., 86%, pneumococcal isolates serotyped. Nonvaccine types and serotypes in the 23-valent pneumococcal polysaccharide vaccine (PPV23), yet not in the 13-valent pneumococcal conjugate vaccine (PCV13) predominated relative to PCV7 and other PCV13 serotypes.

The most prevalent serotypes across childhood cases remained consistent with pre-pandemic levels in 2021. Serotypes 19A, 3, and 19F continued to dominate among PCV13 cases. The most significant decline in the additional PPV23 serotypes was seen in serotype 12F, which led to 20% of PPV23 infections in the pre-pandemic phase but was undetected from July to December of 2021.

Additionally, from 2% before the pandemic to 13% during 2021, more infections were attributable to PPV23 serotype 11A. The nonvaccine serotypes showed no significant alterations, according to the researchers.

Compared to the time before the pandemic, more IPD infections in 2021 exhibited bacteremia. Pneumonia, meningitis, and other clinical symptoms comprised a similar percentage of cases. The 30-day case-mortality rates during the pre-and post-pandemic periods were comparable.

Conclusion

In summary, the study findings showed that while total IPD cases were fewer in 2021 than in the three years before the COVID-19 pandemic, elevations in childhood cases above pre-pandemic levels could indicate hikes in cases among all age categories. The authors stated that a high childhood PCV13 uptake is essential for ongoing population protection.