High risk groups for severe COVID-19 in a whole of population cohort in Australia.

BACKGROUND: Increasing age is the strongest known risk factor for severe COVID-19 disease but information on other factors is more limited. METHODS: All cases of COVID-19 diagnosed from January-October 2020 in New South Wales Australia were followed for COVID-19-related hospitalisations, intensive care unit (ICU) admissions and deaths through record linkage. Adjusted hazard ratios (aHR) for severe COVID-19 disease, measured by hospitalisation or death, or very severe COVID-19, measured by ICU admission or death according to age, sex, socioeconomic status and co-morbidities were estimated. RESULTS: Of 4054 confirmed cases, 468 (11.5%) were classified as having severe COVID-19 and 190 (4.7%) as having very severe disease. After adjusting for sex, socioeconomic status and comorbidities, increasing age led to the greatest risk of very severe disease. Compared to those 30-39 years, the aHR for ICU or death from COVID-19 was 4.45 in those 70-79 years; 8.43 in those 80-89 years; 16.19 in those 90+ years. After age, relative risks for very severe disease associated with other factors were more moderate: males vs females aHR 1.40 (95%CI 1.04-1.88); immunosuppressive conditions vs none aHR 2.20 (1.35-3.57); diabetes vs none aHR 1.88 (1.33-2.67); chronic lung disease vs none aHR 1.68 (1.18-2.38); obesity vs not obese aHR 1.52 (1.05-2.21). More comorbidities was associated with significantly greater risk; comparing those with 3+ comorbidities to those with none, aHR 5.34 (3.15-9.04). CONCLUSIONS: In a setting with high COVID-19 case ascertainment and almost complete case follow-up, we found the risk of very severe disease varies by age, sex and presence of comorbidities. This variation should be considered in targeting prevention strategies.

Whole of population-based cohort study of recovery time from COVID-19 in New South Wales Australia.

BACKGROUND: COVID-19 results in persisting symptoms but there is little systematically collected data estimating recovery time following infection. METHODS: We followed 94% of all COVID-19 cases diagnosed in the Australian state of New South Wales between January and May 2020 using 3-4 weekly telephone interviews and linkage to hospitalisation and death data to determine if they had recovered from COVID-19 based on symptom resolution. Proportional hazards models with competing risks were used to estimate time to recovery adjusted for age and gender. FINDINGS: In analyses 2904 cases were followed for recovery (median follow-up time 16 days, range 1-122, IQR 11-24).There were 2572 (88.6%) who reported resolution of symptoms (262/2572 were also hospitalised), 224 (7.8%) had not recovered at last contact (28/224 were also hospitalised), 51 (1.8%) died of COVID-19, and 57 (2.0%) were hospitalised without a documented recovery date. Of those followed, 20% recovered by 10 days, 60% at 20, 80% at 30, 91% at 60, 93% at 90 and 96% at 120 days. Compared to those aged 30-49 years, those 0-29 years were more likely to recover (aHR 1.22, 95%CI 1.10-1.34) while those aged 50-69 and 70+ years were less likely to recover (aHR respectively 0.74, 95%CI 0.67-0.81 and 0.63, 95%CI 0.56-0.71). Men were faster to recover than women (aHR 1.20, 95%CI 1.11-1.29) and those with pre-existing co-morbidities took longer to recover than those without (aHR 0.90, 95%CI 0.83-0.98). INTERPRETATION: In a setting where most cases of COVID-19 were ascertained and followed, 80% of those with COVID-19 recover within a month, but about 5% will continue to experience symptoms 3 months later. FUNDING: NSW Health Emergency Response Priority Research Projects.

Hospital outcomes after a COVID-19 diagnosis from January to May 2020 in New South Wales Australia.

OBJECTIVE: To describe hospitalisation rates following COVID-19 infection in NSW. DESIGN, SETTING AND PARTICIPANTS: Analysis of all confirmed COVID-19 cases diagnosed in NSW from 1 January to 31 May 2020 extracted from the NSW Notifiable Conditions Information Management System and linked to routinely collected hospitalisation data. OUTCOME MEASURES: In-patient hospitalisations and hospital service utilisation details. RESULTS: There were 3,101 COVID-19 cases diagnosed between 1 January and 31 May 2020 in NSW: mean age 46.7 years, 50.5% were females. Overall, 12.5% (n = 389) had a record of inpatient hospitalisation, 4.2% (n = 130) were admitted to ICU and 1.9% (n = 58) received ventilation. Among adult cases, hospital and ICU admission rates increased with increasing age: 2.9% of those aged 20-29 years were hospitalised, increasing to 46.6% of those aged 80-89 years; 0.6% of those aged 20-29 years were admitted to ICU, increasing to 11.2% of those aged 70-79 years. The median time from symptoms to hospitalisation was seven days (IQR 4-11). The median time in hospital was nine days (IQR 4-20), and in ICU six days (IQR 2-15); the median time in hospital increased with older age. Almost half (49.4%) of those hospitalised with a diagnostic code had pneumonia/lower respiratory tract infection and another 36.6% had an upper respiratory tract infection or other known COVID-19 symptoms. CONCLUSION: COVID-19 is a serious infection particularly in older adults. During January to May of 2020, 1 in 8 of those diagnosed in NSW were hospitalised. While this partly reflects the cautious approach to case management in the initial phase of the pandemic, it also demonstrates the large potential impact of COVID-19 on Australian health services and need for continuing mitigation strategies.

Gonorrhoea enhanced surveillance for indigenous status and risk factors in the south-eastern Sydney population

Background: Gonorrhoea incidence is increasing in the Australian population. As a laboratory notifiable disease in NSW, information is not routinely available on indigenous status, sexual preference or other risk factors for infection. We conducted a 12-month pilot of enhanced surveillance in south-eastern Sydney in order to assess the feasibility of gathering this additional information. Methods: For each notification in a south-eastern Sydney resident with a 2013 specimen date, we sent a letter and questionnaire to the requesting doctor seeking additional demographic and risk factor information. Results: Of 1,341 questionnaires sent, 1,073 (79.5%) were returned, and men comprised 947 (88.3%). Indigenous status was provided for 1,009 (94.1%) cases, with seven (0.7%) identified as Aboriginal or Torres Strait Islander. Most men (83%) but a minority of women (19%) had same sex partners (p<0.001). Whilst 70% of men reported acquisition from a casual partner, only 46% of women thought they had acquired infection from a casual partner. Conclusions: The high response rate and completeness of indigenous status were strong features of this enhanced surveillance pilot which also provided valuable information on sexual preference and other risk factors for infection. However, gathering of this information was very labour intensive for both clinical and public health staff.

Annual vaccine-preventable disease report for New South Wales, Australia, 2014.

This report provides an epidemiological description of selected vaccine-preventable diseases in New South Wales (NSW), Australia, for 2014 to inform ongoing disease monitoring and control efforts. A trend of increasing pertussis notifications was observed, beginning midway through 2014 with the highest disease rates in the 5-9 year age group. Measles notifications increased to 67 cases in 2014 from 34 cases in 2013. Measles cases were associated with travel-related importations-predominantly from the Philippines-and secondary transmission increased compared to 2013 involving three main disease clusters. Notifications of invasive meningococcal disease continued to decline across the state with meningococcal B remaining the most common serogroup in NSW. Increasing rates of pertussis notifications from mid-2014 may indicate the beginning of an epidemic, ending the period of low transmission observed in 2013 and the first half of 2014. An increase in measles notifications in 2014, including secondary transmission, indicates the continued need for public health actions including robust follow-up and awareness campaigns.

New South Wales annual vaccine-preventable disease report, 2013.

AIM: To describe the epidemiology of selected vaccine-preventable diseases in New South Wales, Australia for 2013. METHODS: Data from the New South Wales Notifiable Conditions Information Management System were analysed by local health district of residence, age, Aboriginality, vaccination status and organism. Risk factor and vaccination status data were collected by public health units. RESULTS: Pertussis notification rates in infants were low, and no infant pertussis deaths were reported. Despite a high number of imported measles cases, there was limited secondary transmission. The invasive meningococcal disease notification rate declined, and disease due to serogroup C remained low and stable. CONCLUSION: Vaccine-preventable diseases were relatively well controlled in New South Wales in 2013, with declining or stable notification rates in most diseases compared with the previous year.

New South Wales annual vaccine-preventable disease report, 2013

Aim:To describe the epidemiology of selected vaccine-preventable diseases in New South Wales, Australia for 2013.Methods:Data from the New South Wales Notifiable Conditions Information Management System were analysed by local health district of residence, age, Aboriginality, vaccination status and organism. Risk factor and vaccination status data were collected by public health units.Results:Pertussis notification rates in infants were low, and no infant pertussis deaths were reported. Despite a high number of imported measles cases, there was limited secondary transmission. The invasive meningococcal disease notification rate declined, and disease due to serogroup C remained low and stable.Conclusion:Vaccine-preventable diseases were relatively well controlled in New South Wales in 2013, with declining or stable notification rates in most diseases compared with the previous year.

A state-wide information campaign during a pertussis epidemic in New South Wales, 2010.

Pertussis notifications increased dramatically in New South Wales in 2008, exceeding the rates in previous epidemic years. A state-wide, multi-faceted campaign was launched in March 2009 to provide information about pertussis prevention. A population-based survey was conducted using a Computer Assisted Telephone Interviewing facility to assess the effectiveness of sending letters to households with young infants. A representative sample of 1,200 adults across all 8 area health services was interviewed between July 2009 and September 2010, with responses weighted against the state population. Many respondents (39.7%) reported receiving the letter, while fewer (29.6%) reported receiving an adult pertussis booster in the last year, mostly in response to General Practitioner advice (40.4%). Letter receipt was associated with the uptake of an adult pertussis booster in the past 12 months by respondents (OR 5.8; 95%CI 4.1, 8.2) and other adults in the household (OR 5.1; 95%CI 3.5, 7.5), as well as knowledge about pertussis prevention. Health providers remain crucial for vaccination decision making; however letters may have contributed to an increased uptake of pertussis booster vaccination and knowledge. Health authorities may consider mailing households in future pertussis epidemics as a component of a wider communication strategy.

Parental Tdap boosters and infant pertussis: a case-control study.

BACKGROUND: Although recommended for almost a decade, evidence for field effectiveness of vaccinating close adult contacts of newborn infants against pertussis ("cocooning") is lacking. We evaluated the impact of a government-funded cocoon program during a pertussis epidemic in New South Wales, Australia. METHODS: We matched all New South Wales laboratory-confirmed pertussis cases aged <4 months with onset between April 1, 2009, to March 30, 2011 to controls from the state birth register by date of birth and area of residence. Parental vaccine receipt was by self-report, with a subset verified. Parents were considered "immunized" if vaccinated ≥4 weeks before case symptom onset. The effectiveness of parental immunization (versus neither vaccinated) was quantified as (1 - odds ratio) × 100%. RESULTS: Case households had fewer immunized mothers (22% vs 32%) or fathers (20% vs 31%) but were more likely to include additional and older children. After adjustment, when both parents met our definition of immunized, risk of pertussis at<4 months of age was reduced by 51% (95% confidence interval 10% to 73%). Maternal vaccination prepregnancy and an immunized father reduced the risk by 51% (95% confidence interval 0% to 76%). CONCLUSIONS: Timely parental pertussis boosters provided significant protection. Evidence of protection from maternal vaccination prepregnancy is biologically plausible, and more precise data on the magnitude and duration of this is important for future policy recommendations.

New South Wales annual vaccine-preventable disease report, 2012.

We aim to describe the epidemiology of selected vaccine-preventable diseases in New South Wales (NSW) for 2012. Data from the NSW Notifiable Conditions Information Management System were analysed by: local health district of residence, age, Aboriginality, vaccination status and organism, where available. Risk factor and vaccination status data were collected by public health units for cases following notification under the NSW Public Health Act 2010. The largest outbreak of measles since 1998 was reported in 2012. Pacific Islander and Aboriginal people were at higher risk as were infants less than 12 months of age. Notifications of invasive pneumococcal disease (IPD) in children less than five years declined; however, the overall number of notifications for IPD increased. Mumps case notifications were also elevated. There were no Haemophilus influenzae type b case notifications in children less than five years of age for the first time since the vaccine was introduced. Invasive meningococcal disease case notifications were at their lowest rates since case notification began in 1991. Case notification rates for other selected vaccine-preventable diseases remained stable. Vaccine-preventable disease control is continually strengthening in NSW with notable successes in invasive bacterial infections. However, strengthening measles immunization in Pacific Islander and Aboriginal communities remains essential to maintain measles elimination.

Testing-adjusted chlamydia notification trends in New South Wales, Australia, 2000 to 2010.

INTRODUCTION: Between 2005 and 2010, Australian notification rates for chlamydia infection increased by 64% from 203 to 333 per 100 000 population. Interpreting this trend is difficult without examining rates and local patterns of testing. We examined the effect of adjusting for local testing rates on chlamydia notification trends in New South Wales (NSW), Australia from 2000 to 2010. METHODS: We used testing data for NSW residents for Medicare Benefits Schedule items for chlamydia from 1 July 1999 to 30 June 2005 and 1 July 2007 to 30 June 2010. This data set excluded testing by public sector laboratories. We also obtained laboratory-confirmed genital chlamydia notifications in NSW residents for 1 July 1999 to 30 June 2010 and excluded notifications from public laboratories. We used negative binomial regression to assess trends in chlamydia notification rates by age and sex after adjusting for local government area (LGA)-level Medicare-funded testing rates, socioeconomic disadvantage, remoteness and Medicare provider density. RESULTS: Testing-adjusted rates of chlamydia notifications declined by 5.2% per annum (rate ratio [RR] = 0.95, 95% confidence interval (CI) = 0.93-0.96) for women overall, and 2.3% (RR = 0.98, 95% CI = 0.96-1.00) and 5.0% per annum (RR = 0.95, 95% CI = 0.93-0.98) for men in LGAs with moderate and high densities of Medicare providers, respectively. Notification rates remained stable for men in low Medicare provider density LGAs (RR = 1.01, 95% CI = 0.96-1.07). DISCUSSION: It is likely that increased testing for chlamydia has driven increases in chlamydia notification in NSW over the last decade. Notification data provide no evidence for a general increase in the prevalence of chlamydia in the NSW community for this period. Notification-based chlamydia surveillance should be routinely adjusted for local testing rates.

Testing-adjusted chlamydia notification trends in New South Wales, Australia, 2000 to 2010

Introduction:Between 2005 and 2010, Australian notification rates for chlamydia infection increased by 64% from 203 to 333 per 100 000 population. Interpreting this trend is difficult without examining rates and local patterns of testing. We examined the effect of adjusting for local testing rates on chlamydia notification trends in New South Wales (NSW), Australia from 2000 to 2010. Methods:We used testing data for NSW residents for Medicare Benefits Schedule items for chlamydia from 1 July 1999 to 30 June 2005 and 1 July 2007 to 30 June 2010. This data set excluded testing by public sector laboratories. We also obtained laboratory-confirmed genital chlamydia notifications in NSW residents for 1 July 1999 to 30 June 2010 and excluded notifications from public laboratories. We used negative binomial regression to assess trends in chlamydia notification rates by age and sex after adjusting for local government area (LGA)-level Medicare-funded testing rates, socioeconomic disadvantage, remoteness and Medicare provider density. Results:Testing-adjusted rates of chlamydia notifications declined by 5.2% per annum (rate ratio [RR] = 0.95, 95% confidence interval (CI) = 0.93–0.96) for women overall, and 2.3% (RR = 0.98, 95% CI = 0.96–1.00) and 5.0% per annum (RR = 0.95, 95% CI = 0.93–0.98) for men in LGAs with moderate and high densities of Medicare providers, respectively. Notification rates remained stable for men in low Medicare provider density LGAs (RR = 1.01, 95% CI = 0.96–1.07). Discussion:It is likely that increased testing for chlamydia has driven increases in chlamydia notification in NSW over the last decade. Notification data provide no evidence for a general increase in the prevalence of chlamydia in the NSW community for this period. Notification-based chlamydia surveillance should be routinely adjusted for local testing rates.

Relationship between the population incidence of pertussis in children in New South Wales, Australia and emergency department visits with cough: a time series analysis.

BACKGROUND: Little is known about the potential of syndromic surveillance to provide early warning of pertussis outbreaks. We conducted a time series analysis to assess whether an emergency department (ED) cough syndrome would respond to changes in the incidence of pertussis in children aged under 10 years in New South Wales (NSW), Australia, and to evaluate the timing of any association. A further aim was to assess the lag between the onset of pertussis symptoms and case notification in the infectious diseases surveillance system in NSW. METHODS: Using routinely collected data, we prepared a daily count time series of visits to NSW EDs assigned a provisional diagnosis of cough. Separate daily series were prepared for three independent variables: notifications of cases of pertussis and influenza and ED visits with bronchiolitis (a proxy measure of respiratory syncytial virus (RSV) infection). The study period was 1/1/2007-31/12/2010. A negative binomial multivariate model was used to assess associations between the outcome and independent variables. We also evaluated the median delay in days between the estimated onset of a case of pertussis and the date the local public health authority was notified of that case. RESULTS: When notified pertussis increased by 10 cases in one day, ED visits with cough increased by 5.2% (95% confidence interval (CI): 0.5%-10.0%) seven days later. Daily increases in the other independent variables had a smaller impact on cough visits. When notified influenza increased by 10 cases in one day, ED visits with cough increased by 0.8% (95% CI: 0%-1.7%) seven days later. When ED visits with bronchiolitis increased by 10 visits in one day, ED visits with cough increased by 4.8% (95% CI: 1.2%-8.6%) one day earlier. The median interval between estimated onset of pertussis and case notification was seven days. CONCLUSIONS: Pertussis appears to be an important driver of ED visits with cough in children aged under 10 years. However, the median delay in notification of cases of pertussis was similar to the lag in the pertussis-associated short-term increases in ED visits with cough. Elevations in RSV and influenza activity may also explain increases in the ED cough syndrome. Real time monitoring of ED visits with cough in children is therefore unlikely to consistently detect a potential outbreak of pertussis before passive surveillance.

NSW Annual vaccine-preventable disease report, 2011.

AIM: To describe the epidemiology of selected vaccine-preventable diseases in NSW for 2011. METHODS: Data from the NSW Notifiable Conditions Information Management System were analysed by: local health district of residence, age, Aboriginality, vaccination status, and organism, where available. Risk factor and vaccination status data were collected by public health units for case-patients following notification under the NSW Public Health Act 1991*. RESULTS: Outbreaks of measles and pertussis were reported in 2011, associated with unimmunised groups for measles, and a variety of factors for pertussis. Notification rates for other selected vaccine-preventable diseases remained stable. CONCLUSION: Vaccine-preventable diseases are generally well controlled in NSW. However, pertussis remains an important public health issue. To prevent measles high population vaccination coverage, including vaccination in risk groups, is essential.

EpiReview: Measles in NSW, 2002-2011.

Measles has been eliminated in NSW for more than a decade; however outbreaks associated with international travel do occur. This EpiReview describes the epidemiology of measles in NSW from 2002-2011. A total of 281 cases of measles were notified during the period, an average annual notification rate of 0.41 notifications per 100 000 population (range: 0.06-1.25). There were 139 hospitalisations recorded with a measles diagnosis in the 10-year reporting period, corresponding to a rate of 0.20 hospitalisations per 100 000 population. Of the 80 measles virus specimens genotyped, five genotypes were identified: D9 (38%), D8 (24%), D4 (16%), D5 (14%) with H1 identified less frequently (9%). No single genotype was associated with local transmission across successive years. To sustain good measles control, children should be vaccinated against measles on time through routine childhood immunisation, and all young adults who travel internationally should be vaccinated. Clinician awareness remains important in the early identification and control of measles to avoid further transmission during outbreaks and to enable the timely implementation of public health measures.

NSW annual vaccine-preventable disease report, 2010.

AIMS: To describe trends in case notification data for vaccine-preventable diseases in NSW for 2010. METHODS: Risk factor and vaccination status data were collected from cases through public health unit follow-up. Data from the NSW Notifiable Conditions Information Management System (NCIMS) were analysed by: local health district of residence; age; vaccination status; and sub-organism, where available. RESULTS: Outbreaks of measles and pertussis were notified in 2010, associated with unimmunised groups (measles) or as a result of waning immunity (pertussis). CONCLUSION: With the exception of pertussis, most vaccine-preventable disease notifications remain low in NSW. Ensuring high levels of vaccination for travellers is important to prevent future outbreaks of vaccine-preventable disease, particularly measles.

Case-control study of risk factors for hospitalization caused by pandemic (H1N1) 2009.

We conducted a case-control study to identify risk factors for hospitalization from pandemic (H1N1) 2009 virus infection among persons >16 years of age in Sydney, Australia. The study comprised 302 case-patients and 603 controls. In a logistic regression model, after adjusting for age and sex, risk factors for hospitalization were pregnancy (odds ratio [OR] 22.4, 95% confidence interval [CI] 9.2-54.5), immune suppression (OR 5.5, 95% CI 2.8-10.9), pre-existing lung disease (OR 6.6, 95% CI 3.8-11.6), asthma requiring regular preventive medication (OR 4.3, 95% CI 2.7-6.8), heart disease (OR 2.3, 95% CI 1.2-4.1), diabetes (OR 3.8, 95% CI 2.2-6.5), and current smoker (OR 2.0, 95% CI 1.3-3.2) or previously smoked (OR 2.0, 95% CI 1.3-3.0). Although obesity was not independently associated with hospitalization, it was associated with an increased risk of requiring mechanical ventilation. Public health messages should give greater emphasis on the risk for severe disease among pregnant women and smokers.

Staff immunisation: policy and practice in child care.

AIM: The aims of this study were to determine the level of knowledge among child-care centre directors regarding the National Health and Medical Research Council (NHMRC) recommendations for the immunisation of child-care workers, the extent to which this knowledge was translated into practice and any organisational barriers to the development and implementation of staff immunisation policy. METHODS: A cross-sectional survey, conducted in August 2006, in which a postal questionnaire was sent to a random sample of 784 NSW child-care centres. Centre directors were asked to complete the questionnaire on immunisation knowledge, policy and practice for the centre. A multivariate logistic-regression model was used to identify factors independently associated with centres with an immunisation policy for staff and centres that offered to pay all or part of the cost of vaccination of staff. RESULTS: Directors from 437 centres participated in the study for a response rate of 56%. Of these, 49% were aware of the NHMRC recommendations, and 57% had a staff immunisation policy in place. In the logistic regression model, centres with a written immunisation policy for staff were more likely to be aware of the NHMRC guidelines and offer long day care services. Centres that offered to pay all or part of the cost of immunisation for staff were more likely to be aware of the NHMRC guidelines, offer other child-care services and not operate for profit. Barriers to staff immunisation were related to the implementation of policy and included cost, time and access to information. CONCLUSIONS: The level of awareness of specific staff immunisation recommendations was relatively low. The transition of knowledge to policy was encouraging, although implementation of policies requires further commitment.

Review of the 2008-2009 pertussis epidemic in NSW: notifications and hospitalisations.

In 2008 and 2009 increased numbers of pertussis notifications were reported in NSW. During the epidemic period, the pertussis notification rate was 2.7 times higher than the previous 5-year average. Rates of pertussis notifications and hospitalisations were highest among infants aged less than 1 year across all years studied. Compared to previous years, the notification rate for children aged 1-4 years increased dramatically and was particularly striking for children aged 3 years with notifications exceeding those for infants in 2009. Changes in testing practices during the epidemic period, including a significant increase in the use of polymerase chain reaction, may account for some of the relative increase in size of the 2008-2009 outbreak compared with previous outbreak years.

Pandemic (H1N1) 2009 influenza in NSW: an overview of the public health response.

In April 2009, a new influenza A virus, pandemic (H1N1) 2009 influenza, was identified in Mexico and the United States of America. The NSW response was co-ordinated by the Public Health Emergency Operations Centre through an incident control structure that included planning, operations and logistics teams with designated roles and responsibilities for the public health response. The emphasis of public health action changed as the pandemic moved through three response phases: DELAY, CONTAIN and PROTECT. This article describes the NSW public health response to the 2009 influenza pandemic from the perspective of the NSW Department of Health.