International links between Streptococcus pneumoniae vaccine serotype 4 sequence type (ST) 801 in Northern European shipyard outbreaks of invasive pneumococcal disease.

BACKGROUND: Pneumococcal disease outbreaks of vaccine preventable serotype 4 sequence type (ST)801 in shipyards have been reported in several countries. We aimed to use genomics to establish any international links between them. METHODS: Sequence data from ST801-related outbreak isolates from Norway (n = 17), Finland (n = 11) and Northern Ireland (n = 2) were combined with invasive pneumococcal disease surveillance from the respective countries, and ST801-related genomes from an international collection (n = 41 of > 40,000), totalling 106 genomes. Raw data were mapped and recombination excluded before phylogenetic dating. RESULTS: Outbreak isolates were relatively diverse, with up to 100 SNPs (single nucleotide polymorphisms) and a common ancestor estimated around the year 2000. However, 19 Norwegian and Finnish isolates were nearly indistinguishable (0-2 SNPs) with the common ancestor dated around 2017. CONCLUSION: The total diversity of ST801 within the outbreaks could not be explained by recent transmission alone, suggesting that harsh environmental and associated living conditions reported in the shipyards may facilitate invasion of colonising pneumococci. However, near identical strains in the Norwegian and Finnish outbreaks does suggest that transmission between international shipyards also contributed to those outbreaks. This indicates the need for improved preventative measures in this working population including pneumococcal vaccination.

Easy access to vaccination was important for adherence during the 2016-2019 HPV catch-up vaccination in Norway.

Between September and October 2019, the Norwegian Institute for Public Health (NIPH) surveyed women born between 1991 and 1996 who were offered catch-up vaccination for human papilloma virus (HPV). The aim was to identify determinants of vaccine schedule adherence. A random sample of 10,000 women who were offered catch-up vaccination were invited to participate in the survey. We defined adherence as receiving all three doses. Determinants of HPV vaccination adherence were investigated using descriptive, univariable and multivariable logistic regression analyses providing adjusted odds ratios (aOR). Data from 3,762 respondents who received at least one dose were included. Overall, 92.1% (95% CI = 89.3-91.9) of those initiating vaccination adhered to the complete schedule. The following factors were significantly associated with HPV vaccination adherence compared to non-adherence: country of origin (aOR = 0.43; 95% CI = 0.47-0.97), having children (aOR = 0.51; 95% CI = 0.35-0.73), ease of finding out where to get vaccinated (aOR = 1.94; 95% CI = 1.69-2.23), preference for receiving information from health authorities (aOR = 1.37; 95% CI = 1.04-1.81) and vaccination being readily available (aOR = 2.28; 95% CI = 1.50-3.37). Information from NIPH via SMS and social media were negatively associated for Norwegians (aOR = 0.68, 95% CI = 0.46-1.01) and positively associated for those whose country of origin was not Norway (aOR = 1.48, 95% CI = 0.69-3.14; not significant). Those who did not adhere to the full vaccination schedule reported that they had forgotten (40.4%; 95% CI = 33.5-47.8) or had no time (32.9%; 95% CI = 26.2-40.4). Despite NIPH's targeted communication campaign, the main barriers for HPV vaccination adherence were difficulty to find out where to get the vaccine, forgetting to take the vaccine or not having time to complete the schedule.

Sociodemographic determinants of catch-up HPV vaccination completion between 2016-2019 in Norway.

Between 2016 and 2019, a catch-up human papillomavirus (HPV) vaccination took place in Norway for women born between 1991 and 1996. The aim of this study was to identify sociodemographic determinants of complete vaccination (3 doses) and partial vaccination (1-2 doses). A random sample of 10,000 women who were offered catch-up HPV vaccination were invited. We assessed the association between sociodemographic characteristics and vaccination completion using univariable and multivariable multinomial logistic regression.Of 4,967 respondents, 3,464 (63%) received complete vaccination and 298 (7%) received partial vaccination. 30% did not receive any vaccination and functioned as reference group. Compared with having Norwegian caregivers, having a caregiver from non-western countries decreased the odds of partial and complete vaccination (aOR = 0.57; 95%CI = 0.35-0.95 and aOR = 0.57; 95%CI = 0.44-0.74). Having a caregiver from other western countries decreased the odds of complete vaccination (aOR = 0.72; 95%CI = 0.52-0.98). Residing in Norway for 10 years or longer significantly increased the odds of complete vaccination (aOR = 2.65; 95%CI = 1.58-4.43). Being in a relationship significantly increased the odds of partial vaccination compared with being single (aOR = 1.50; 95%CI = 1.02-2.21). Being married (aOR = 0.66; 95%CI = 0.50-0.86) and having children (aOR = 0.53; 95%CI = 0.42-0.68) decreased the odds of complete vaccination. Having university education increased the odds of both partial and complete vaccination (aOR = 2.19; 95%CI = 1.47-3.25 and aOR = 4.11; 95%CI = 3.33-5.06).Having a caregiver born outside of Norway, having children and being married decreased the odds of receiving complete HPV vaccination. This highlights the need to target communication around HPV vaccination toward different ethnic communities and include more specific messaging that having children and being married does not necessarily prevent HPV infections.

Changes in pneumococcal carriage prevalence and factors associated with carriage in Norwegian children, four years after introduction of PCV13.

BACKGROUND: Streptococcus pneumoniae carriage is often asymptomatic but can cause invasive pneumococcal disease. Pneumococcal carriage is a prerequisite for disease, with children as main reservoir and transmitters. Childhood carriage can therefore be used to determine which serotypes circulate in the population and which may cause disease in the non-vaccinated population. In 2006, a pneumococcal conjugate vaccine (PCV7) was introduced into the Norwegian Childhood Immunisation Programme, which was replaced by the more valent PCV13 in 2011. We investigated changes in pneumococcal carriage prevalence 4 years after switching to PCV13 compared to three previous surveys, and analysed factors associated with carriage in children. METHODS: We conducted a cross-sectional study in Norway, autumn 2015, among children attending day-care centres. We collected questionnaire data and nasopharyngeal swabs to identify pneumococcal serotypes. We compared the carriage prevalence in 2015 with surveys conducted in the same setting performed before widespread vaccination (2006; n = 610), 2 years after PCV7 introduction (2008; n = 600), and 2 years after switching to PCV13 (2013; n = 874). Using multilevel logistic regression we determined the association between pneumococcal carriage and previously associated factors. RESULTS: In 2015, 896 children participated, with age ranging from 8 to 80 months. The overall carriage prevalence was 48/100 children [95%CI 44-53] in 2015, 38% [29-46] lower than in 2006 pre-PCV7, and 23% [12-32] lower than in 2013, 2 years after switching to PCV13. The PCV13 carriage prevalence was 2.8/100 children [1.9-4.2] in 2015. Increasing age (p < 0.001), recent antimicrobial use (odds ratio = 0.42 [0.21-0.57]) and being vaccinated (odds ratio = 0.37 [0.29-0.47]) were negatively associated with carriage. CONCLUSIONS: Our study showed a continued decrease in overall pneumococcal carriage, mainly fuelled by the decline in vaccine serotypes after vaccine introduction. Childhood vaccination with PCV13 should be continued to keep low PCV13 carriage, transmission and disease. Furthermore, the low prevalence of PCV13-type carriage in children endorse the choice of not recommending PCV13 in addition to the 23-valent pneumococcal polysaccharide vaccine to most medical risk groups in Norway, as little disease caused by these serotypes can be expected.

Are ready-to-eat salads ready to eat? An outbreak of Salmonella Coeln linked to imported, mixed, pre-washed and bagged salad, Norway, November 2013.

We investigated a nationwide outbreak of Salmonella Coeln in Norway, including 26 cases identified between 20 October 2013 and 4 January 2014. We performed a matched case-control study, environmental investigation and detailed traceback of food purchases to identify the source of the outbreak. In the case-control study, cases were found to be more likely than controls to have consumed a ready-to-eat salad mix (matched odds ratio 20, 95% confidence interval 2·7-∞). By traceback of purchases one brand of ready-to-eat salad was indicated, but all environmental samples were negative for Salmonella. This outbreak underlines that pre-washed and bagged salads carry a risk of infection despite thorough cleaning procedures by the importer. To further reduce the risk of infection by consumption of ready-to-eat salads product quality should be ensured by importers. Outbreaks linked to salads reinforce the importance of implementation of appropriate food safety management systems, including good practices in lettuce production.

Antibiotic prescriptions and cycles of Mycoplasma pneumoniae infections in Norway: can a nationwide prescription register be used for surveillance?

Mycoplasma pneumoniae outbreaks cause increased use of macrolides and tetracyclines. We aimed to investigate whether drug use data, in addition to laboratory data, could improve understanding of the spread of M. pneumoniae epidemics. Number of users of Mycoplasma antibiotics (erythromycin, doxycycline, clarithromycin) per week and county of residence in an indicator age group (6-12 years) was retrieved from the Norwegian prescription database for the epidemic season 2011-2012 and compared to non-epidemic seasons. In 2011, increased use of Mycoplasma antibiotics was first observed in September on the west coast of Norway. The Norwegian laboratory-based surveillance system showed the first increase in positive tests in August 2011 and an epidemic was announced on 25 October 2011. At that time the use of Mycoplasma antibiotics had already exceeded three times the use in non-epidemic periods. Data for three counties from the regional microbiological laboratories showed that the increase in number of positive samples coincided in time with the increase in prescription data. Laboratory data cannot accurately determine the extent of an epidemic, and drug use data cannot identify the cause. Establishing a systematic interaction between the two monitoring systems will enhance surveillance and probably contribute to improved infection control and prudent antibiotic prescribing.

Analysis of Bordetella pertussis clinical isolates circulating in European countries during the period 1998-2012.

Despite more than 50 years of vaccination, pertussis is still an endemic disease, with regular epidemic outbreaks. With the exception of Poland, European countries have replaced whole-cell vaccines (WCVs) by acellular vaccines (ACVs) in the 1990s. Worldwide, antigenic divergence in vaccine antigens has been found between vaccine strains and circulating strains. In this work, 466 Bordetella pertussis isolates collected in the period 1998-2012 from 13 European countries were characterised by multi-locus antigen sequence typing (MAST) of the pertussis toxin promoter (ptxP) and of the genes coding for proteins used in the ACVs: pertussis toxin (Ptx), pertactin (Prn), type 2 fimbriae (Fim2) and type 3 fimbriae (Fim3). Isolates were further characterised by fimbrial serotyping, multi-locus variable-number tandem repeat analysis (MLVA) and pulsed-field gel electrophoresis (PFGE). The results showed a very similar B. pertussis population for 12 countries using ACVs, while Poland, which uses a WCV, was quite distinct, suggesting that ACVs and WCVs select for different B. pertussis populations. This study forms a baseline for future studies on the effect of vaccination programmes on B. pertussis populations.

Investigations into the emergence of pertactin-deficient Bordetella pertussis isolates in six European countries, 1996 to 2012.

Pathogen adaptation has been proposed to contribute to the resurgence of pertussis. A striking recent example is the emergence of isolates deficient in the vaccine component pertactin (Prn). This study explores the emergence of such Prn-deficient isolates in six European countries. During 2007 to 2009, 0/83 isolates from the Netherlands, 0/18 from the United Kingdom, 0/17 Finland, 0/23 Denmark, 4/99 Sweden and 5/20 from Norway of the isolates collected were Prn-deficient. In the Netherlands and Sweden, respectively 4/146 and 1/8 were observed in a later period (2010­12). The Prn-deficient isolates were genetically diverse and different mutations were found to inactivate the prn gene. These are indications that Prn-deficiency is subject to positive selective pressure. We hypothesise that the switch from whole cell to acellular pertussis vaccines has affected the balance between 'costs and benefits' of Prn production by Bordetella pertussis to the extent that isolates that do not produce Prn are able to expand. The absence of Prn-deficient isolates in some countries may point to ways to prevent or delay the spread of Prn-deficient strains. In order to substantiate this hypothesis, trends in the European B. pertussis population should be monitored continuously.

A review of the evidence to inform pneumococcal vaccine recommendations for risk groups aged 2 years and older.

For decades, vaccination with the 23-valent polysaccharide pneumococcal vaccine (PPV23) has been available for risk groups aged ⩾2 years to prevent invasive pneumococcal disease (IPD). Recently, a 13-valent pneumococcal conjugated vaccine (PCV13) has been licensed for use in all age groups. PCV13 may induce better protection than PPV23 because of different immunogenic properties. This called for a revision of vaccine recommendations for risk groups. We therefore reviewed literature on risk groups for IPD, and effectiveness and safety of pneumococcal vaccines and supplemented that with information from public health institutes, expert consultations and data on IPD epidemiology. We included 187 articles. We discuss the implications of the heterogenic vulnerability for IPD within and between risk groups, large indirect effects of childhood immunization, and limited knowledge on additional clinical benefits of PCV13 in combination with PPV23 for the Norwegian recommendations. These are now step-wise and consider the need for vaccination, choice of pneumococcal vaccines, and re-vaccination interval by risk group.

Outbreak of wound botulism in people who inject drugs, Norway, October to November 2013.

In October and November 2013, four cases of wound botulism were confirmed in people who inject drugs (PWID) in Norway. Two additional cases are suspected. Because of the international distribution pathways for heroin ­ the likely source of the outbreak ­ healthcare workers and public health authorities in other countries should remain vigilant for wound botulism in PWID. This outbreak serves as a reminder that countries should ensure access to botulinum antitoxin in case of outbreak situations.

Increased incidence of Mycoplasma pneumoniae infection in Norway 2011.

Epidemics of Mycoplasma pneumoniae have recently been reported from England and Wales and from Denmark. A similar increase in M. pneumoniae infections was noted in Norway late autumn 2011.The epidemic has resulted in shortage of erythromycin and the use of alternative antibiotics has been recommended.

Two cases of verified clinical failures using internationally recommended first-line cefixime for gonorrhoea treatment, Norway, 2010.

Neisseria gonorrhoeae has developed resistance to most of the available therapeutic antimicrobials. The susceptibility to extended-spectrum cephalosporins, the last remaining first-line treatment option, is decreasing globally. This report describes the first two cases outside Japan of verified gonorrhoea clinical failures using internationally recommended first-line cefixime treatment. Enhanced awareness and more frequent follow-up examination, test-of-cure and appropriate verification/falsification of presumed clinical treatment failures, involving several clinical and laboratory parameters should be strongly emphasised worldwide.