Browsing by Author "Ricketson, Leah"
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- ItemOpen AccessInvasive Pneumococcal Disease During the COVID-19 Pandemic in Calgary, Canada(2022-06-20) Ricketson, Leah; Kellner, James; CASPER InvestigatorsSimilar to other regions and countries, there was a dramatic decline in the incidence of IPD and other contagious infectious diseases in Calgary after the start of the COVID-19 pandemic. The initial decline in overall IPD incidence (IRR 0.22 in 2nd quarter of 2020 vs average for 2011-19) was particularly dramatic and was sustained until mid-2021 in adults and the end of 2021 in children. Presumably, the reduction was related to society-side measures implemented to reduce transmission of the SARS-CoV-2 virus, with such measures also reducing the transmission of other contagious diseases including pneumococcus and influenza. These measures were highest in 2020 and gradually reduced through 2021. In addition, IPD uncommonly occurs as a complication of SARS-CoV-2 infections, unlike other viruses such as influenza and RSV, where secondary pneumococcal infections occur readily. The higher rebound in PCV13 serotype IPD in adults in 2021 (compared with non-PCV13 serotype IPD) of interest. Childhood PCV programs have demonstrated a strong herd-protection effect to prevent vaccine-serotype IPD in adults. There was a significant decline in routine childhood vaccination rates in Alberta in 2020 (https://bmjopen.bmj.com/content/12/1/e055968). There may be an association between such declines and a reduction in the level of herd protection that influences vaccine-serotype IPD in adults.
- ItemOpen AccessPneumococcal Disease Trends in the Post-Vaccine Era in Calgary, Canada: An Interrupted Time Series Analysis(2022-06-20) Ricketson, Leah; Kellner, James D; CASPER InvestigatorsBackground: In 2002 the 4-dose 7-valent pneumococcal conjugate vaccine (PCV7) was introduced in Calgary for vaccination of children, followed by the 3-dose 13-valent vaccine (PCV13) in 2010. Methods: We conducted an interrupted time series analysis on incidence of IPD per quarter allowing for change in trends in 2002 and 2010. We included models for IPD overall and age and serotype restricted models. Results: The incidence of PCV7 IPD (all ages) decreased after PCV7 introduction in 2002 (P<0.001) and was sustained after PCV13 introduction in 2010. In children, the incidence of PCV13 (less PCV7 ST) IPD increased in children after PCV7 introduction (P<0.001) and decreased after PCV13 introduction (P=0.002). After PCV7 introduction, overall IPD incidence was lower in children, but not significant, (P=0.054) and was unchanged in adults (P=0.4721). After PCV13 introduction, overall IPD incidence was unchanged in children (P=0.88) and increased in adults (P<0.001). Conclusions: PCV7 IPD has declined in the post-PCV period, but overall IPD had not declined significantly and was increasing in adults prior to the precipitous decline observed in 2021, during the COVID-19 pandemic. PCV13 serotypes, as well as non-vaccine serotypes, continue to cause disease, including outbreaks of serotype 4, 5, and 8. It is unclear whether the change from 4 doses to 3 doses of PCV has reduced overall vaccine effectiveness.
- ItemOpen AccessSerotype Groups & Antibiotic Resistance in Invasive Pneumococcal Disease (IPD) Isolates & Lower Respiratory Infection (LRTI) Isolates of Streptococcus pneumoniae: A CASPER Study(2022-06-14) Ricketson, Leah; Lemay, Julie-Anne; Kellner, James; CASPER InvestigatorsA considerably higher proportion of LRTI isolates have STs that are not included in current vaccines, compared with IPD isolates. The proportion of IPD and LRTI isolates with PCV13 STs has declined during the PCV13 era. If PCV15 and/or PCV20 are implemented, a higher proportion of IPD and LRTI cases will be covered however the proportion of LRTI isolates covered will be a minority of all cases. Pneumococcal resistance to penicillin has generally declined or remained low overall for many years in both IPD and LRTI isolates at all ages in our population, with the exception of serotype 19A, where resistance increased particularly in LRTI isolates and in children (data not shown). Multidrug resistance (MDR) is most common in serotype 19A and in LRTI isolates and is primarily due to resistance to three or more of erythromycin, clindamycin, TMP/SMX, cefuroxime and tetracycline.