The impact of the COVID-19 pandemic on gastrointestinal infection trends in England, February – July 2020

Nk, Love; Elliot, Alex J; Rm, Chalmers; Douglas, Amy; Gharbia, Saheer E.; McCormick, Jacquelyn; Hughes, Helen E.; Morbey, Roger; Oliver, Isabel; Vivancos, Roberto; Smith, Gillian

doi:10.1101/2021.04.06.21254174

Cited by 8 publications

(11 citation statements)

References 21 publications

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“…COVID-19 restrictions had a significant effect on the number of cases of gastrointestinal illness (GI) in England and Wales including Cryptosporidium (28), and in this study we have identified that they impacted both C. hominis and C. parvum. anecdotally there were many news stories covering this phenomenon, particularly involving parties and swimming in rivers.…”

Section: Discussionmentioning

confidence: 76%

“…Most gastrointestinal infections reduced dramatically during the COVID-19 pandemic (37) as childcare and educational settings were closed and eating establishments’ opening hours and social / leisure activities were curtailed. Our hypothesis was that the COVID-19 restrictions might have altered the epidemiology of cryptosporidiosis by infecting species and by time, place and person.…”

Section: Discussionmentioning

confidence: 99%

“…Reductions in GI illness were observed across all surveillance indicators as COVID-19 started to peak. Compared with the 5-year average (2015-2019), there was a 52% reduction in GI outbreaks reported during the first 6 months of the COVID-19 response (28). We aimed to assess if COVID-19 restrictions caused a significant change to the epidemiology of C. parvum and C. hominis.…”

Section: Introductionmentioning

confidence: 99%

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Impact of the COVID-19 restrictions on the epidemiology ofCryptosporidiumspp. in England and Wales, 2015-2021

Adamson

Chalmers

Thomas

et al. 2022

Preprint

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Background In England and Wales, cryptosporidiosis cases peak in spring and autumn, usually associated with zoonotic and environmental exposures (Cryptosporidium parvum, spring/autumn) and with overseas travel and water-based activities (Cryptosporidium hominis, autumn). Restrictions to control the COVID-19 pandemic prevented social mixing and access to swimming pools and restaurants for many months. Foreign travel from the UK also reduced by 74% in 2020. However, these restrictions potentially increased environmental exposures as people sought alternative countryside activities locally. To inform and strengthen surveillance programmes, we investigated the impact of COVID-19 restrictions on the epidemiology of C. hominis and C. parvum cases. MethodsCryptosporidium-positive stools, with case demographic data, are referred routinely for genotyping to the national Cryptosporidium Reference Unit (CRU). Cases were extracted from the CRU database (01 January 2015 to 31 December 2021). We defined two periods for pre- and post-COVID-19 restrictions implementation corresponding to the first UK-wide lockdown on 23 March 2020: pre-restrictions between week 1, 2015 and week 12, 2020, and post restrictions-implementation between week 13, 2020 and week 52, 2021. We conducted an interrupted time-series analysis, assessing differences in C. parvum and C. hominis incidence, trends and periodicity between these periods using negative binomial regression with linear-splines and interactions. Results There were 21,304 cases between 01 January 2015 and 31 December 2021 (C. parvum = 12,246; C. hominis = 9,058). Post restrictions-implementation incidence of C. hominis dropped by 97.5% (95%CI: 95.4%-98.6%; p<0.001). The decreasing incidence-trend observed pre-restrictions (IRR=0.9976; 95%CI: 0.9969-0.9982; p<0.001) was not observed post restrictions-implementation (IRR=1.0081; 95%CI: 0.9978-1.0186; p=0.128) due to lack of cases. No periodicity change was observed post restrictions-implementation. Where recorded, 22% of C. hominis cases had travelled abroad. There was also a strong social gradient, with those who lived in deprived areas experiencing a higher proportion of cases. This gradient did not exist post restrictions-implementation, but the effect was exacerbated for the most deprived: 27.2% of cases from the most deprived decile compared to 12.7% in the pre-restrictions period. For C. parvum, post restrictions-implementation incidence fell by 49.0% (95%CI: 38.4%-58.3%; p<0.001). There was no pre-restrictions incidence-trend (IRR=1.0003; 95%CI: 0.9997-1.0009; p=0.322) but a slight increasing incidence-trend existed post restrictions-implementation (IRR=1.0071; 95%CI: 1.0038-1.0104; p<0.001). A periodicity change was observed for C. parvum post restrictions-implementation, peaking one week earlier in spring and two weeks later in autumn. Where recorded, 8% of C. parvum cases had travelled abroad. The social gradient observed for C. parvum was inverse to that for C. hominis, and was stable pre-restrictions and post restrictions-implementation. ConclusionC. hominis cases were almost entirely arrested post restrictions-implementation, reinforcing that foreign travel is a major driver of seeding infections. Increased hand-hygiene, reduced social mixing, limited access to swimming pools and limited foreign travel affected incidence of most gastrointestinal (GI) pathogens, including Cryptosporidium, in the same period. C. parvum incidence fell sharply but recovered throughout the post restrictions-implementation period, back to pre-restrictions levels by the end of 2021; this is consistent with relaxation of restrictions, reduced compliance and increased countryside use. The effect on our results of changes in health-seeking behaviours, healthcare access and diagnostic laboratory practices post restrictions-implementation is uncertain, but it is likely that access to GPs and specimen referral rate to CRU decreased. Future exceedance reporting for C. hominis should exclude the post restrictions-implementation period but retain it for C. parvum (except the first six weeks post restrictions-implementation where the incidence fell sharply). Advice on infection prevention and control should be improved for people with GI symptoms, including returning travellers, to ensure hand hygiene and appropriate swimming pool avoidance.

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Section: Discussionmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impact of the COVID-19 restrictions on the epidemiology ofCryptosporidiumspp. in England and Wales, 2015-2021

Adamson

Chalmers

Thomas

et al. 2022

Preprint

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“…By sequence analysis of the gp60 gene, 31/40 (78%) typable C. hominis samples were subtype IbA10G2 which predominates in the UK and much of Europe [ 31 ], but our epidemiological findings may not translate to settings where other subtypes are more prevalent. Since this work was completed, there has been a dramatic change in the epidemiology of Cryptosporidium in the UK with C. parvum becoming the predominant species during the COVID-19 pandemic, following lockdown interventions at the end of March 2020 [ 60 ]. This is currently under investigation by time series analysis.…”

Section: Discussionmentioning

confidence: 99%

Cross-sectional household transmission study of Cryptosporidium shows that C. hominis infections are a key risk factor for spread

et al. 2022

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Background Infection with the Cryptosporidium parasite causes over 4000 cases of diagnosed illness (cryptosporidiosis) in England and Wales each year. The incidence of sporadic disease has not been sufficiently established, and how frequently this arises from contact with other infected people is not well documented. This project aimed to explore potential transmission in the home and attempt to identify asymptomatic infections, which might play a role in transmission. Risk factors and characteristics associated with spread of infection in the home were described including any differences between Cryptosporidium species. Methods The study identified cryptosporidiosis cases from North West England and Wales over a year and invited them and their household to take part. Each household was sent a study pack containing study information and a questionnaire, and stool sample kits to provide samples from consenting household members. Cryptosporidium-positive stool samples, identified by immunofluorescence microscopy, were characterised using molecular methods to help describe any patterns of transmission. Characteristics of households with and without additional cases were described, and compared using odds ratios (OR) and a multivariable logistic regression identified independent risk factors for household transmission. Data collection ran for one year, beginning in September 2018 with an initial pilot phase. Results We enrolled 128 index cases and their households. Additional illness occurred in over a quarter of homes, each reporting an average of two additional cases. The majority of these were undiagnosed and unreported to surveillance. This burden was even greater in households where the index case was infected with C. hominis versus C. parvum, or the index case was under five years old, with mums and siblings most at risk of secondary infection. Only having an index case of C. hominis was independently associated with transmission in the multivariable model (OR 4.46; p = 0.01). Conclusions Cryptosporidium was a considerable burden in the home. At-risk homes were those where the index was less than five years old and/or infected with C. hominis. Of particular risk were female caregivers and siblings. Hygiene advice should be specifically directed here. This work provides evidence for humans as sources of C. hominis infection and that person-person is a key pathway. We recommend that all stools submitted for the investigation of gastrointestinal pathogens are tested for Cryptosporidium to better capture cases, inclusion of speciation data in routine surveillance, and the consideration of specific clinical advice on prevention for high-risk homes.

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“…The number of reported gastrointestinal infection outbreaks in England in the first six months of 2020 was less than half the previous five year average, found a study in BMJ Open 1. Laboratory confirmed infections fell by a third (27 859 cases, against a five year average of 42 495), the researchers found.…”

Section: Covid-19mentioning

confidence: 92%

Seven days in medicine: 16-22 March

2022

BMJ

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The impact of the COVID-19 pandemic on gastrointestinal infection trends in England, February – July 2020

Cited by 8 publications

References 21 publications

Impact of the COVID-19 restrictions on the epidemiology ofCryptosporidiumspp. in England and Wales, 2015-2021

Impact of the COVID-19 restrictions on the epidemiology ofCryptosporidiumspp. in England and Wales, 2015-2021

Cross-sectional household transmission study of Cryptosporidium shows that C. hominis infections are a key risk factor for spread

Seven days in medicine: 16-22 March

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