ABSTRACT
OBJECTIVEUsing data from European prospective household studies, we systematically compared the symptom burden of the wild-type and Alpha variant infected individuals versus the Omicron BA.1 and BA.2 infected individuals across paediatric and adult age-groups. In addition, we measured the impact of COVID-19 vaccination on the Omicron symptom burden. METHODSThe household transmission studies were conducted during the wild-type and Alpha period (April 2020 to April 2021) and the early Omicron BA.1 and BA.2 dominant period (January to March 2022). All three studies used similar protocols. Households were prospectively followed from detection of the first SARS-CoV-2 index case until at least day 21 including (repeated) PCR testing, paired serology and daily symptom reporting for all household members. To avoid possible index-case ascertainment bias, we restricted analyses to secondary household cases. Age-stratified SARS-CoV-2 symptom burden was compared for wild-type/Alpha versus Omicron infections and for primary versus primary plus booster series vaccinated adult cases. FINDINGSIn total 216 secondary cases from wild-type/Alpha, and 130 from the Omicron period were included. Unvaccinated children <12 years experienced more symptoms and higher maximum and cumulative severity scores during the Omicron compared to the wild-type/Alpha period (p=0.004, p=0.011 and p=0.075, respectively). In adults, disease duration and maximum and cumulative severity scores were reduced during the Omicron period. Adjusted for age, gender and prior immunity Omicron was associated with lower odds for loss of smell or taste (Odds Ratio [OR]: 0.14; 95%CI 0.03-0.50), and higher, but non-significant odds for upper respiratory symptoms, fever and fatigue (ORs varying between 1.85-2.23). Comparing primary versus primary plus booster vaccinated adult cases during the Omicron period no differences were observed in disease severity or duration (p[≥]0.12). INTERPRETATIONIn children, the Omicron variant causes higher symptom burden compared to the wild-type/Alpha. Adults experienced a lower symptom burden possibly due to prior vaccination. A shift in most frequently reported symptoms occurred with a marked reduction in loss of smell or taste during the Omicron period. An additional effect of booster vaccination on symptom severity in infected adults compared to primary series only, could not be demonstrated.
Subject(s)
Fever , COVID-19 , FatigueABSTRACT
AIMThe CoKids study aimed to estimate the community incidence of symptomatic and asymptomatic SARS-CoV-2 in children and parents and to assess the symptomatology of SARS-COV-2 infections relative to SARS-CoV-2 negative respiratory episodes. METHODSIn this prospective study, households with at least one child <18 years were recruited from three existing Dutch cohorts. Participation included SARS-CoV-2 screening at 4-6 weeks intervals for all household members during 23 weeks of follow-up and active reporting of new onset respiratory symptoms until July 1st 2021. Follow-up was temporarily intensified following new onset respiratory symptoms in a household member or a SARS-CoV-2 positive screening test and included daily symptom recording, repeated PCR testing (nose-throat, saliva and fecal samples) and SARS-CoV-2 antibody measurement (paired dried blood spots) in all household members. Age-stratified incidence rates for SARS-CoV-2 positive and negative episodes were calculated. Symptomatology and disease burden of respiratory episodes were compared by SARS-CoV-2 status and age. RESULTSIn total 307 households were enrolled including 1209 subjects. We detected 64 SARS-CoV-2 positive and 118 SARS-CoV-2 negative respiratory outbreaks. The highest incidence rate was found in children <12 years for SARS-CoV-2 negative episodes (0.93/ person-year (PY); 95%CI: 0.88-0.96). The SARS-CoV-2 incidence in this age-group was 0.21/PY for confirmed only, and 0.41/PY if probable cases were included. SARS-CoV-2 incidence did not differ by age group (p>0.27). Nasal congestion/runny nose, with or without cough and fatigue were the three most prevalent symptom clusters for both SARS-CoV-2 positive and negative respiratory episodes. Among children, no differences were observed in the symptomatology and severity of SARS-CoV-2 positive versus negative respiratory episodes, whereas among adults, SARS-CoV-2 positive episodes had a higher number and severity of symptoms and with a longer duration p<0.001). CONCLUSIONUsing active, longitudinal household follow up, we detected a high incidence rate of SARS-CoV-2 infections in children that was similar to adults. The findings suggest that after 20 months of COVID-19 pandemic, up to 2/3 of Dutch children < 12 years have been infected with SARS-CoV-2. Symptomatology and disease severity of SARS-CoV-2 in children is similar to respiratory illness from other causes. In adults, SARS-COV-2 positive episodes are characterized by more and prolonged symptoms, and higher severity. These findings may assist decisions on COVID-19 policies targeting children.
Subject(s)
Severe Acute Respiratory Syndrome , Cough , COVID-19 , Fatigue , Respiratory InsufficiencyABSTRACT
Objectives: To describe the SARS-CoV-2 viral load distribution in different patient groups and age categories. Methods: All SARS-CoV-2 RT-PCR results from nasopharyngeal (NP) and oropharyngeal (OP) swabs (first PCR from unique patients only) that were collected between January 1 and December 1, 2020, in the Public Health Services regions Kennemerland and Hollands Noorden, province of Northern Holland, the Netherlands were included in this study. Swabs were derived from patients with respiratory symptoms who were presented at the general practitioner (GP) or hospital, hospital health care workers (HCWs) of four regional hospitals, nursing home residents and HCWs of multiple nursing homes, and in majority (>75%) from Public Health testing facilities of the two Public Health Services. SARS-CoV-2 PCR crossing point (Cp) values were used to estimate viral loads (higher Cp-values indicate lower viral loads). Results: In total, 278.470 unique patients were tested of whom 9.1% (n=25.365) were SARS-CoV-2 positive. As there were differences in viral load distribution between tested populations, further analyses focused on PCRs performed by public health services (n=211.933) where sampling and inclusion were uniform. These data present reveal a clear relation between age and SARS-CoV-2 viral load, with especially children aged<12 years showing lower viral loads than shown in adults ({beta}: -0.03, 95CI% -0.03 to -0.02, p<0.001), independent of sex and/or symptom duration. Interestingly, the median Cp values between the oldest (>79 years) and youngest (<12 years) population differed by over 4 PCR cycles, suggesting approximately a 16 fold difference in viral load. In addition, the proportion of children aged < 12 years with a Cp-value >30 was significantly higher compared to the other patients (31.1% vs. 16.9%, p-value<0.001). Conclusion: We observed that in patients tested by public health services, SARS-CoV2 viral load increases significantly with age. Previous studies suggest that young children (<12 years) play a limited role in SARS-CoV-2 transmission. Currently, the relation between viral load and infectivity is not yet well understood, and further studies should elucidate whether the lower viral load in children is indeed related to their suggested limited role in SARS-CoV-2 transmission. Moreover, as antigen tests are less sensitive than PCR, these results suggest that SARS-CoV-2 antigen tests could have lower sensitivity in children than in adults.