COVID-19 Pandemic Significantly Impacts Pneumococcal Mortality Trends

Pneumococcal disease mortality trends changed significantly in the US following the onset of the COVID-19 pandemic, according to a study published in the International Journal of Infectious Diseases.¹ With lower rates than normal from the start of the pandemic to early 2021, followed by a spike in pneumococcus mortality in mid-2021, the study highlighted the complexities behind the confluence of respiratory viruses.

“Pneumococcus is an important bacterial pathogen that causes a range of conditions, including pneumonia, otitis media, and invasive pneumococcal disease (IPD),” wrote the authors of the study. “IPD is defined based on the isolation of pneumococcus from normally sterile sites such as blood and cerebrospinal fluid.”

As continuous research on the COVID-19 pandemic’s overall impact is released, one aspect of the phenomenon’s events is how the pandemic impacted other respiratory disease rates. According to a study published in Viruses, SARS-CoV-2 unsurprisingly became the dominant pathogen amid respiratory viruses. As a result, researchers saw influenza pathogens “virtually disappear,” while influenza A, rhinovirus, and enterovirus all experienced a resurgence in the postpandemic time period.²

Researchers explored the pneumococcal mortality rates and trends among patients 25 or older during the COVID-19 pandemic. | image credit: lllCklll / stock.adobe.com

READ MORE: PCV10 Among Children Indirectly Protected Unvaccinated Adults

With notable decreases and increases in respiratory viruses throughout the pandemic, many researchers may share the sentiment that COVID-19 significantly staggered the public’s understanding and surveillance of other respiratory diseases.

For pneumococcal diseases specifically, the trends in disease and hospitalization rates during and after the pandemic further reinforce the complexities of COVID-19. In a study from the Journal of the Pediatric Infectious Diseases Society, pediatric IPD rates per 100,000 hospital admissions decreased dramatically following COVID-19 lockdowns.³

Despite nonCOVID-19 respiratory viruses declining during the pandemic, possibly due to countrywide shutdowns and a decreased risk of spreading diseases, there is still conflicting evidence regarding pneumococcus disease and mortality before, after, and during the pandemic.

“While prior studies have documented decreases in the rate of IPD during the pandemic, there has been little consideration for how the pandemic might have influenced rates of death due to pneumococcal disease,” continued the authors.¹ “In this study, we evaluated changes in rates of deaths recorded as being related to pneumococcus during the post-pandemic period using nationwide vital statistics data from the United States and evaluated changes in the characteristics of these deaths.”

Using National Center for Health Statistics data, researchers explored the death statistics of patients 25 or older. Their primary study outcome was death from pneumococcal disease. They also further stratified the data and detailed the mortality rates from patients with pneumococcal pneumonia and nonrespiratory IPD.

From 2014 to 2022, encompassing pre- and postpandemic time periods, pneumococcal disease was responsible for a total of 8590 deaths (53% men; 26.2% aged 50 to 64 years) in US patients 25 and older. Of these pneumococcal-related mortality rates, pneumococcal pneumonia accounted for 6068 deaths and nonrespiratory IPD for 2522 deaths.

Researchers then delved into the patterns in mortality rate changes during the pandemic, as well as the additional changes observed following its peak.

“For most of 2020, including the early months of the COVID-19 pandemic when the US was experiencing lockdowns, the reported deaths were not notably different from the prepandemic period and largely followed the typical seasonal pattern,” they wrote.¹ “However, at the end of 2020 and early 2021, when pneumococcal deaths would typically peak, the rates of death remained lower than normal and stayed lower than expected in the spring of 2021.”

Following these trends, pneumococcal deaths reverted in mid-2021, spiking above baseline alongside the surge of the Delta COVID-19 wave. By the time the winter season of 2021 rolled around, pneumococcal mortality rates had returned to the normal seasonal trends observed prior to the pandemic.

The researchers of this study observed unprecedented pneumococcal mortality trends triggered by the COVID-19 pandemic. With a significant decrease followed by an immediate spike that was later reduced, data show that disease surveillance was even further impacted than experts once expected.

Reasons behind the decrease in pneumococcal carriage, according to the authors, may be how public health interventions disrupted disease transmission. For the subsequent spike that followed, researchers believe that the SARS-CoV-2 virus could be a trigger for pneumococcal disease, the same way it can trigger influenza and respiratory syncytial virus.

“In summary, pneumococcal mortality patterns changed significantly after the onset of the COVID-19 pandemic, as reflected by a marked reduction during the initial winter wave that aligned with changes in respiratory virus activity,” concluded the authors.¹ “There was a notable surge of pneumococcal death coinciding with Delta wave of COVID-19 which could not be explained by influenza or RSV, suggesting the potential role of SARS-CoV-2 as a trigger for pneumococcal disease. Our findings highlighted the influence of respiratory viruses on the development and severity of pneumococcal disease.”

READ MORE: Pneumococcal Resource Center

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References

1. Shang L, Perniciaro S, Weinberger DM. Changes in pneumococcal deaths in the United States following the COVID-19 pandemic. IJID. Published online August 29, 2025:108020. https://doi.org/10.1016/j.ijid.2025.108020

2. Manno M, Pavia G, Gigliotti S, et al. Respiratory virus prevalence across pre-, during-, and post-SARS-CoV-2 pandemic periods. Viruses. 2025 Jul 25;17(8):1040. doi: 10.3390/v17081040.

3. Sarmiento Clemente A, Kaplan SL, Barson WJ, et al. Decrease in pediatric invasive pneumococcal disease during the COVID-19 pandemic. JPIDS. 2022;11(9):426-428. https://doi.org/10.1093/jpids/piac056