Increased Incidence of Invasive Pneumococcal Disease among Children after COVID-19 Pandemic, England.

During July-December 2021, after COVID-19 restrictions were removed in England, invasive pneumococcal disease incidence in children <15 years of age was higher (1.96/100,000 children) than during the same period in 2020 (0.7/100,000 children) and in prepandemic years 2017-2019 (1.43/100,000 children). Childhood vaccine coverage should be maintained to protect the population.

Invasive Pneumococcal Disease in People With Human Immunodeficiency Virus in England, 1999-2017.

BACKGROUND: The 7-valent and 13-valent pneumococcal conjugate vaccines (PCVs) were introduced into the UK childhood immunization program in 2006 and 2010, respectively, with high effectiveness and resulting in both direct and indirect protection. We describe the epidemiology of invasive pneumococcal disease (IPD) in adults with human immunodeficiency virus (HIV) in England following the introduction of both PCVs. METHODS: Data on a national cohort of people with HIV were linked to confirmed IPD cases in adults aged ≥ 15 years during 1999-2017. Date of HIV infection was estimated using a CD4 slope decline algorithm. RESULTS: Among 133 994 adults with HIV, 1453 developed IPD during 1999-2017, with 70% (1016/1453) developing IPD ≥ 3 months after their HIV diagnosis. IPD and HIV were codiagnosed within 90 days in 345 (24%) individuals. A missed opportunity for earlier HIV diagnosis was identified in 6% (89/1453), mostly in earlier years. IPD incidence in people with HIV increased from 147/100 000 in 1999 to 284/100 000 in 2007 before declining and stabilizing between 92 and 113/100 000 during 2014-2017. Mean annual IPD incidence was lower among those receiving antiretroviral therapy during 2014-17 (68 vs 720/100 000; incidence rate ratio [IRR] 9.3; 95% confidence interval [CI], 7.3-11.8; P < .001) and was markedly lower in those with a suppressed viral load (50 vs 523/100 000; IRR 10.4; 95% CI, 7.6-14.1; P < .001). The latter group still had 4.5-fold higher (95% CI, 3.8-5.3; P < .001) IPD incidence compared to the general population (11.2/100 000). CONCLUSIONS: IPD incidence among people with HIV reduced after PCV13 introduction and has remained stable. Adults presenting with IPD should continue to be tested for HIV infection.

Impact of the Coronavirus Disease 2019 (COVID-19) Pandemic on Invasive Pneumococcal Disease and Risk of Pneumococcal Coinfection With Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): Prospective National Cohort Study, England.

BACKGROUND: Streptococcus pneumoniae coinfection with influenza results in synergistic lethality, but there are limited data on pneumococcal coinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: Public Health England conducts invasive pneumococcal disease (IPD) and SARS-CoV-2 surveillance in England. IPD trends during 2000/2001-2019/2020 epidemiological years were analyzed and cases during February-June 2020 linked with laboratory-confirmed SARS-CoV-2 infections. Multivariable logistic regression was used to assess risk factors for death. RESULTS: IPD incidence in 2019/2020 (7.6/100 000; n = 3964) was 30% (IRR, .70; 95% CI, .18-2.67) lower compared with 2018/2019 (10.9/100 000; n = 5666), with large reductions observed across all age groups during March-June 2020. There were 160 886 SARS-CoV-2 and 1137 IPD cases during February-June 2020, including 40 IPD/coronavirus disease 2019 (COVID-19) co-infections (.025% [95% CI, .018-.034] of SARS-CoV-2 infections; 3.5% [2.5-4.8] of IPD cases), 21 with COVID-19 diagnosed 3-27 days after IPD, and 27 who developed COVID-19 ≥28 days after IPD. Case-fatality rates (CFRs) were 62.5 (25/40), 47.6% (10/21), and 33.3% (9/27), respectively (P < .001). In addition to an independent association with increasing age and serotype group, CFR was 7.8-fold (95% CI, 3.8-15.8) higher in those with IPD/COVID-19 coinfection and 3.9-fold (95% CI, 1.4-10.7) higher in patients who developed COVID-19 3-27 days after IPD compared with patients with IPD only. CONCLUSIONS: Large declines in IPD were observed following COVID-19 lockdown. IPD/COVID-19 coinfections were rare but associated with high CFR, mainly in older adults. The rarity, age and serotype distribution of IPD/COVID-19 coinfections do not support wider extension of pneumococcal vaccination.

Structural, Genetic, and Serological Elucidation of Streptococcus pneumoniae Serogroup 24 Serotypes: Discovery of a New Serotype, 24C, with a Variable Capsule Structure.

Pneumococcal capsules are important in pneumococcal pathogenesis and vaccine development. Although conjugate vaccines have brought about a significant reduction in invasive pneumococcal disease (IPD) caused by vaccine serotypes, the relative serotype prevalence has shifted with the dramatic emergence of serotype 24F in some countries. Here, we describe 14 isolates (13 IPD and 1 non-IPD) expressing a new capsule type, 24C, which resembles 24F but has a novel serological profile. We also describe the antigenic, biochemical, and genetic basis of 24F and 24C and the related serotypes 24A and 24B. Structural studies show that 24B, 24C, and 24F have identical polysaccharide backbones [ß-Ribf-(1→4)-α-Rhap-(1→3)-ß-GlcpNAc-(1→4)-ß-Rhap-(1→4)-ß-Glcp] but with different side chains, as follows: 24F has arabinitol-phosphate and 24B has ribitol-phosphate. 24C has a mixture of 24F and 24B repeating units, with the ratio of ribitol to arabinitol being strain dependent. In contrast, the 24A capsule has a backbone without ß-Ribf but with arabinitol-phosphate and phosphocholine side chains. These structures indicate that factor-sera 24d and 24e recognize arabinitol and ribitol, respectively, which explains the serology of serogroup 24, including those of 24C. The structures can be genetically described by the bispecificity of wcxG, which is capable of transferring arabinitol or ribitol when arabinitol is limiting. Arabinitol is likely not produced in 24B but is produced in reduced amounts in 24C due to various mutations in abpA or abpB genes. Our findings demonstrate how pneumococci modulate their capsule structure and immunologic properties with small genetic changes, thereby evading host immune responses. Our findings also suggest a potential for new capsule types within serogroup 24.

Persistent Circulation of Vaccine Serotypes and Serotype Replacement After 5 Years of Infant Immunization With 13-Valent Pneumococcal Conjugate Vaccine in the United Kingdom.

BACKGROUND: Following programmatic introduction of the 13-valent pneumococcal conjugate vaccine (PCV13), there is residual carriage and disease due to PCV13-covered serotypes. METHODS: PCV13-immunized children aged 13-48 months, N = 988, were enrolled between February 2014 and August 2015 ("late PCV13"), and had nasopharyngeal pneumococcal carriage compared with 7-valent pneumococcal conjugate vaccine (PCV7) immunized children, N = 567, enrolled between November 2010 and September 2011 ("early PCV13"). Nasopharyngeal pneumococci were molecular-serotyped by microarray. Invasive pneumococcal disease (IPD) cases were identified through enhanced national surveillance. RESULTS: Compared with PCV7-immunized children, carriage among PCV13-immunized children was significantly lower for serotypes 19A (odds ratio [OR], 0.08 [95% confidence interval {CI}, .02-.25]), 6C (OR, 0.11 [95% CI, .03-.32]), and 7F (8 vs 0 cases). IPD incidence in children <5 years was significantly lower for serotypes 1 (incidence rate ratio [IRR], 0.03 [95% CI, 0-.19]) and 7F (IRR, 0.13 [95% CI, .05-.36]) but not 19A (IRR, 0.6 [95% CI, .3-1.12]) or serotype 3 (IRR, 2.3 [95% CI, .86-6.15]) in the late PCV13 period than in the early PCV13 period. The most significant rises in IPD incidence were for serotypes 8, 12F, and 24F. CONCLUSIONS: PCV13 has reduced serotype 19A carriage among vaccinated children. We found no impact of PCV13 on serotype 3 carriage or disease, and emergence of non-PCV13-serotype disease.

Characteristics of Invasive Pneumococcal Disease Caused by Emerging Serotypes After the Introduction of the 13-Valent Pneumococcal Conjugate Vaccine in England: A Prospective Observational Cohort Study, 2014-2018.

BACKGROUND: England is experiencing a rapid increase in invasive pneumococcal disease (IPD) caused by serotypes 8, 12F, and 9N; their clinical characteristics and outcomes have not been described. METHODS: Public Health England conducts national IPD surveillance. Cases due to emerging serotypes were compared with those included in the 13-valent pneumococcal conjugate vaccine (PCV13) and the remaining non-PCV13 serotypes. RESULTS: There were 21 592 IPD cases during 2014-15 to 2017-18, including 20 108 (93.1%) with serotyped isolates and 17 450 (86.8%) with completed questionnaires. PCV13 serotypes were responsible for 20.1% (n = 4033), while serotype 8 (3881/20 108 [19.3%]), 12F (2365/20 108 [11.8%]), and 9N (1 296/20 108 [6.4%]) were together responsible for 37.5% of cases. Invasive pneumonia was the most common presentation (11 424/16 346 [69.9%]) and, overall, 67.0% (n = 11 033) had an underlying comorbidity. The median age (interquartile range) at IPD due to serotypes 8 (59 [45-72] years) and 12F (56 [41-70] years) was lower than serotype 9N (67 [53-80] years), PCV13 serotypes (68 [52-81] years), and remaining non-PCV13 serotypes (70 [53-82] years). Serotype 9N IPD cases also had higher comorbidity prevalence (748/1087 [68.8%]) compared to serotype 8 (1901/3228 [58.9%]) or 12F (1042/1994 [52.3%]), and higher case fatality (212/1128 [18.8%]) compared to 8.6% (291/3365) or 10.0% (209/2086), respectively. CONCLUSIONS: Serotypes 8 and 12F were more likely to cause IPD in younger, healthier individuals and less likely to be fatal, while serotype 9N affected older adults with comorbidities and had higher case fatality.

Effectiveness of the 23-valent pneumococcal polysaccharide vaccine against vaccine serotype pneumococcal pneumonia in adults: A case-control test-negative design study.

BACKGROUND: Vaccination with the 23-valent pneumococcal polysaccharide vaccine (PPV23) is available in the United Kingdom to adults aged 65 years or older and those in defined clinical risk groups. We evaluated the vaccine effectiveness (VE) of PPV23 against vaccine-type pneumococcal pneumonia in a cohort of adults hospitalised with community-acquired pneumonia (CAP). METHODS AND FINDINGS: Using a case-control test-negative design, a secondary analysis of data was conducted from a prospective cohort study of adults (aged ≥16 years) with CAP hospitalised at 2 university teaching hospitals in Nottingham, England, from September 2013 to August 2018. The exposure of interest was PPV23 vaccination at any time point prior to the index admission. A case was defined as PPV23 serotype-specific pneumococcal pneumonia and a control as non-PPV23 serotype pneumococcal pneumonia or nonpneumococcal pneumonia. Pneumococcal serotypes were identified from urine samples using a multiplex immunoassay or from positive blood cultures. Multivariable logistic regression was used to derive adjusted odds of case status between vaccinated and unvaccinated individuals; VE estimates were calculated as (1 - odds ratio) × 100%. Of 2,357 patients, there were 717 PPV23 cases (48% vaccinated) and 1,640 controls (54.5% vaccinated). The adjusted VE (aVE) estimate against PPV23 serotype disease was 24% (95% CI 5%-40%, p = 0.02). Estimates were similar in analyses restricted to vaccine-eligible patients (n = 1,768, aVE 23%, 95% CI 1%-40%) and patients aged ≥65 years (n = 1,407, aVE 20%, 95% CI -5% to 40%), but not in patients aged ≥75 years (n = 905, aVE 5%, 95% CI -37% to 35%). The aVE estimate in relation to PPV23/non-13-valent pneumococcal conjugate vaccine (PCV13) serotype pneumonia (n = 417 cases, 43.7% vaccinated) was 29% (95% CI 6%-46%). Key limitations of this study are that, due to high vaccination rates, there was a lack of power to reject the null hypothesis of no vaccine effect, and that the study was not large enough to allow robust subgroup analysis in the older age groups. CONCLUSIONS: In the setting of an established national childhood PCV13 vaccination programme, PPV23 vaccination of clinical at-risk patient groups and adults aged ≥65 years provided moderate long-term protection against hospitalisation with PPV23 serotype pneumonia. These findings suggest that PPV23 vaccination may continue to have an important role in adult pneumococcal vaccine policy, including the possibility of revaccination of older adults.

Pneumococcal serotype trends, surveillance and risk factors in UK adult pneumonia, 2013-18.

BACKGROUND: Changes over the last 5 years (2013-18) in the serotypes implicated in adult pneumococcal pneumonia and the patient groups associated with vaccine-type disease are largely unknown. METHODS: We conducted a population-based prospective cohort study of adults admitted to two large university hospitals with community-acquired pneumonia (CAP) between September 2013 and August 2018. Pneumococcal serotypes were identified using a novel 24-valent urinary monoclonal antibody assay and from blood cultures. Trends in incidence rates were compared against national invasive pneumococcal disease (IPD) data. Persons at risk of vaccine-type pneumonia (pneumococcal conjugate vaccine (PCV)13 and pneumococcal polysaccharide vaccine (PPV)23) were determined from multivariate analyses. FINDINGS: Of 2934 adults hospitalised with CAP, 1075 (36.6%) had pneumococcal pneumonia. The annual incidence of pneumococcal pneumonia increased from 32.2 to 48.2 per 100 000 population (2013-18), predominantly due to increases in PCV13non7-serotype and non-vaccine type (NVT)-serotype pneumonia (annual incidence rate ratio 1.12, 95% CI 1.04 to 1.21 and 1.19, 95% CI 1.10 to 1.28, respectively). Incidence trends were broadly similar to IPD data. PCV13non7 (56.9% serotype 3) and PPV23non13 (44.1% serotype 8) serotypes were identified in 349 (32.5%) and 431 (40.1%) patients with pneumococcal pneumonia, respectively. PCV13-serotype pneumonia (dominated by serotype 3) was more likely in patients in the UK pneumococcal vaccination clinical risk group (adjusted OR (aOR) 1.73, 95% CI 1.31 to 2.28) while PPV23-serotype pneumonia was more likely in patients outside the clinical risk group (aOR 1.54, 95% CI 1.13 to 2.10). INTERPRETATION: The incidence of pneumococcal CAP is increasing, predominantly due to NVT serotypes and serotype 3. PPV23-serotype pneumonia is more likely in adults outside currently identified clinical risk groups.

Invasive Pneumococcal Disease in UK Children <1 Year of Age in the Post-13-Valent Pneumococcal Conjugate Vaccine Era: What Are the Risks Now?

BACKGROUND: Invasive pneumococcal disease (IPD) has declined significantly since the introduction of pneumococcal conjugate vaccines (PCVs). It is not known whether certain infant populations remain at higher risk of IPD in countries with established 13-valent PCV (PCV13) programs. We aimed to describe the epidemiology, clinical characteristics, serotype distribution, and outcomes of IPD in infants, and to estimate the relative risk of PCV13-type, non-PCV13-type, and overall IPD in premature infants compared to term infants during a 4-year period after the PCV13 program was established. METHODS: This was a prospective, enhanced national surveillance of laboratory-confirmed IPD in England in infants aged <1 year diagnosed during 2013-2016. RESULTS: There were 517 cases of IPD (incidence: 19/100000 infants). Incidence was significantly higher in premature infants compared with those born at term (49/100000 vs 17/100000; incidence rate ratio [IRR], 2.87; P < .001), with infants born before 28 weeks' gestation having the highest incidence (150/100000; IRR, 8.8; P < .001). Of the 454 IPD cases with serotyped isolates, most were caused by non-PCV13 serotypes (369 cases, 71.4%), with 85 cases (16.4%) due to PCV13 serotypes. There were 31 deaths (case fatality rate [CFR], 6.2% [95% confidence interval, 4.3%-8.6%]). Premature infants did not have a higher CFR than term infants (P = .62). CONCLUSIONS: IPD incidence in infants remains lower than rates reported prior to PCV7 introduction in England. The risk of IPD remains significantly higher in premature infants compared to infants born at term, for both PCV13 and non-PCV13 serotypes. Any changes to the infant PCV13 immunization schedule may disproportionally affect premature infants.

Effect of Pneumococcal Conjugate Vaccines on Pneumococcal Meningitis, England and Wales, July 1, 2000-June 30, 2016.

We describe the effects of the 7-valent (PCV7) and 13-valent (PCV13) pneumococcal conjugate vaccines on pneumococcal meningitis in England and Wales during July 1, 2000-June 30, 2016. Overall, 84,473 laboratory-confirmed invasive pneumococcal disease cases, including 4,160 (4.9%) cases with meningitis, occurred. PCV7 implementation in 2006 did not lower overall pneumococcal meningitis incidence because of replacement with non-PCV7-type meningitis incidence. Replacement with PCV13 in 2010, however, led to a 48% reduction in pneumococcal meningitis incidence by 2015-16. The overall case-fatality rate was 17.5%: 10.7% among patients <5 years of age, 17.3% among patients 5-64 years of age, and 31.9% among patients >65 years of age. Serotype 8 was associated with increased odds of death (adjusted odds ratio 2.9, 95% CI 1.8-4.7). In England and Wales, an effect on pneumococcal meningitis was observed only after PCV13 implementation. Further studies are needed to assess pneumococcal meningitis caused by the replacing serotypes.

Rapid Spread of Pneumococcal Nonvaccine Serotype 7C Previously Associated with Vaccine Serotype 19F, England and Wales.

We observed a sudden and rapid increase in rare invasive pneumococcal disease serotype 7C, from an annual average of 3 cases during 2000-01 through 2015-16 to 29 cases in 2016-17. The increase was caused almost entirely by clonal expansion of sequence type 177, previously associated with vaccine serotype 19F.

Childhood Deaths Attributable to Invasive Pneumococcal Disease in England and Wales, 2006-2014.

BACKGROUND: Pneumococcal conjugate vaccines (PCVs) are highly effective in preventing invasive pneumococcal disease (IPD), but deaths due to IPD still occur. We aimed to describe children who died of IPD since PCV introduction in England and Wales. METHODS: Public Health England conducts enhanced IPD surveillance in England and Wales. IPD cases in PCV-eligible children aged <5 years (born since 4 September 2004 and diagnosed between 4 September 2006 and 3 September 2014) were actively followed up by postal questionnaires and, for fatal cases, detailed information was requested prospectively from multiple sources. RESULTS: During the 8-year period, there were 3146 IPD cases and 150 IPD-related deaths (case fatality rate, 4.8%). Overall, 132 isolates from fatal cases were serotyped (88%) and 35 distinct serotypes were identified, with no serotype predominance. Most deaths occurred in children aged <1 year (88/150 [59%]) and 1-year-olds (36/150 [24%]). One-third (53/150 [35%]) had a known risk factor for IPD. Clinical presentation varied with age but not by serotypes in the different conjugate vaccines. Meningitis was diagnosed in nearly half the fatal cases (71/150 [47%]). The IPD-related mortality rate declined after 7-valent PCV introduction from 1.25/100000 children in 2006-2007 to 0.60/100000 in 2009-2010, with a further reduction following 13-valent PCV introduction from April 2010 to 0.39/100000 in 2013-2014 (14 deaths; incidence rate ratio, 0.31 [95% confidence interval, .16-.61]; P = .0003), when most deaths were due to nonvaccine serotypes or in neonates. CONCLUSIONS: Most fatal IPD cases are currently not vaccine-preventable. Additional strategies will be required to reduce childhood pneumococcal deaths in countries with established pneumococcal vaccination programs.

Characteristics and Serotype Distribution of Childhood Cases of Invasive Pneumococcal Disease Following Pneumococcal Conjugate Vaccination in England and Wales, 2006-2014.

Background: The 7-valent and 13-valent pneumococcal conjugate vaccines (PCV7 and PCV13, respectively) are highly effective in preventing invasive pneumococcal disease (IPD) caused by vaccine serotypes. Vaccine failure (vaccine-type IPD after age-appropriate immunization) is rare. Little is known about the risk, clinical characteristics, or outcomes of PCV13 compared to PCV7 vaccine failure. Methods: Public Health England conducts IPD surveillance and provides a national reference service for serotyping pneumococcal isolates in England and Wales. We compared the epidemiology, rates, risk factors, serotype distribution, clinical characteristics, and outcomes of IPD in children with PCV13 and PCV7 vaccine failure. Results: A total of 163 episodes of PCV failure were confirmed in 161 children over 8 years (4 September 2006 to 3 September 2014) in 10 birth cohorts. After 3 vaccine doses, PCV7 and PCV13 failure rates were 0.19/100000 (95% confidence interval [CI], .10-.33 [57 cases]) and 0.66/100000 (95% CI, .44-.95 [104 cases]) vaccinated person-years, respectively. Children with PCV13 failure were more likely to be healthy (87/105 [82.9%] vs 37/56 [66.1%]; P = .02), present with bacteremic lower respiratory tract infection (LRTI) (61/105 [58.1%] vs 11/56 [19.6%]; P < .001), and develop empyema (41/61 [67.2%] vs 1/11 [9.1%]; P < .001) compared to PCV7 failures. Serotypes 3 (n = 38 [36.2%]) and 19A (n = 30 [28.6%]) were responsible for most PCV13 failures. Six children died (4% [95% CI, 1%-8%]), including 5 with comorbidities. Conclusions: PCV failure is rare and, compared to PCV7 serotypes, the additional PCV13 serotypes are more likely to cause bacteremic LRTI and empyema in healthy vaccinated children.

Nosocomial Outbreak of Drug-Resistant Streptococcus pneumoniae Serotype 9V in an Adult Respiratory Medicine Ward.

Streptococcus pneumoniae infections arising in hospitalized patients are often assumed to be sporadic and linked to community acquisition. Here, whole-genome sequencing was used to demonstrate nosocomial acquisition of antimicrobial-resistant sequence type 156 (ST156) serotype 9V S. pneumoniae in 3 respiratory patients that resulted in two bacteremias and one lower respiratory tract infection. Two of the cases arose in patients who had recently been discharged from the hospital and were readmitted from the community. Nosocomial spread was suspected solely because of the highly unusual resistance pattern and case presentations within 24 h of one another. The outbreak highlights the potential for rapid transmission and the short incubation period in the respiratory ward setting.

Rise of multidrug-resistant non-vaccine serotype 15A Streptococcus pneumoniae in the United Kingdom, 2001 to 2014.

Conjugate vaccines have reduced pneumococcal disease in vaccinated children and unvaccinated adults, but non-vaccine serotypes are of concern, particularly if antibiotic resistant. We reviewed Streptococcus pneumoniae collected via: (i) the British Society for Antimicrobial Chemotherapy (BSAC) surveillances from 2001-2014; (ii) Public Health England's (PHE) invasive isolate surveillance from 2005-2014 and (iii) referral to PHE for resistance investigation from 2005-2014. Serotype 15A increased in all series, with many representatives showing triple resistance to macrolides, tetracyclines and penicillin. 15A was consistently among the 10 most prevalent serotypes from 2011 in PHE and BSAC invasive isolate/bacteraemia surveillance but never previously; 26-33% of these invasive 15A isolates had triple resistance. BSAC respiratory isolates were only serotyped in 2013/14 and 2014/15 (October to September); 15A was most prevalent serotype in both periods, comprising 9-11% of isolates, 38-48% of them with triple resistance. Serotype 15A represented 0-4% of S. pneumoniae referred to PHE for reference investigation annually until 2008 but rose to 29% (2013) and 32% (2014). Almost all multidrug-resistant 15A isolates were sequence type (ST) 63 variants, whereas susceptible 15A isolates were clonally diverse. The rise of serotype 15A suggests that pneumococcal conjugate vaccines will need ongoing adaptation.

Impact of infant 13-valent pneumococcal conjugate vaccine on serotypes in adult pneumonia.

Infant 13-valent pneumococcal conjugate vaccination (PCV13) was introduced to the UK in 2010. Its impact on serotypes implicated in adult non-bacteraemic pneumococcal pneumonia is not known. Beginning in 2008, a 5-year prospective cohort study of adults admitted to hospital with community-acquired pneumonia (CAP) was conducted. Pneumococcal serotype was established using a validated multiplex immunoassay (Bio-Plex; Bio-Rad, Hercules, CA, USA). The overall incidence for hospitalised CAP and pneumococcal CAP was 79.9 (95% CI 76.6-83.3) and 23.4 (95% CI 21.6-25.3) per 100,000 population, respectively. A decline in CAP (incidence rate ratio (IRR) per year 0.96, 95% CI 0.94-0.99; p=0.016) and pneumococcal CAP (IRR per year 0.84, 95% CI 0.80-0.89; p<0.001) was observed over the 5-year period of the study. Between the pre- and post-PCV13 periods of the study, the incidence of CAP due to serotypes included in the PCV7 declined by 88% (IRR 0.12, 95% CI 0.08-0.20; p<0.001), and CAP due to the additional 6 serotypes in PCV13 declined by 30% (IRR 0.70, 95% CI 0.51-0.96; p=0.024). Incidence of adult pneumococcal pneumonia declined over the last 5 years, with serotypes included in PCV13 declining post-PCV13 introduction, indicating early herd protection effects from PCV13 infant vaccination on adult non-bacteraemic disease. These effects may accrue over the coming years with implications for national pneumococcal vaccination policies in adults.

Pneumococcal serotypes in adult non-invasive and invasive pneumonia in relation to child contact and child vaccination status.

BACKGROUND: On a population level, pneumococcal conjugate vaccination in children has reduced the incidence of vaccine-type disease in all age groups, including older adults. Few individual level studies have been performed describing the pneumococcal serotypes associated with adult community acquired pneumonia (CAP) and quantifying associations with child contact and child vaccination status. METHODS: Pneumococcal serotypes were determined using a validated multiplex immunoassay (Bio-Plex) in a large prospective cohort of adults hospitalised with CAP. Child (<16 years old) contact history and child pneumococcal vaccination status were obtained from patients and public health records, respectively. RESULTS: Of 1130 participants, 329 (29.1%) reported child contact, and pneumococcal infection was identified in 410 (36.3%). Pneumococcal CAP was commoner in adults with child contact (148/329 (45.0%) vs 262/801 (32.7%); adjusted OR 1.63, CI 1.25 to 2.14; p<0.001). A serotype was determined in 263 of 410 (64.1%) adults with pneumococcal CAP; 112 (42.6%) reported child contact, 38 (33.9%) with a vaccinated child. Adults in contact with a vaccinated child were significantly less likely to have vaccine-type CAP compared with adults in contact with an unvaccinated child (6 of 38 (15.8%) vs 25 of 74 (33.8%), respectively; OR 0.37, 95% CI 0.14 to 0.99; p=0.044). CONCLUSIONS: Pneumococcal aetiology in adult CAP is independently associated with child contact and implicated serotypes are influenced by child vaccination status. This is the first study to demonstrate these associations at an individual rather than population level; it affirms that 'herd protection' from childhood vaccination extends beyond adult invasive disease to pneumococcal CAP.

Carriage of Streptococcus pneumoniae in adults hospitalised with community-acquired pneumonia.

OBJECTIVES: We aimed to determine the prevalence of and risk factors for nasopharyngeal and oral pneumococcal carriage in adults with community-acquired pneumonia (CAP), and the relationship between carried and disease-causing serotypes. METHODS: Between 2016 and 2018, nasopharyngeal swabs, oral-fluid, and urine were collected from hospitalised adults recruited into a prospective cohort study of CAP. Pneumococcal carriage was detected by semi-quantitative real-time PCR of direct and culture-enriched nasopharyngeal swabs and culture-enriched oral-fluid. LytA and piaB positive/indeterminate samples underwent semi-quantitative serotype/serogroup-specific real-time-PCR. Serotypes in urine were identified using a 24-valent serotype-specific urinary-antigen assay. RESULTS: We included 465 CAP patients. Nasopharyngeal carriage was detected in 34/103 (33.0%) swabbed pneumococcal pneumonia patients and oral carriage in 18/155 (12%) of sampled pneumococcal pneumonia patients. Concordance between nasopharyngeal/urine serotypes and oral/urine serotypes was 70.6% and 50% respectively. Serotypes 3 (26%, 22.2%), 8 (19.7%, 19.4%), non-typeable (11.6%, 13.9%) and 19A/F (7.5%, 8.3%) were most prevalent in urine and nasopharyngeal swabs respectively, with non-typeable (35%) and 15A/F (17%) most prevalent in oral-fluid. Pneumococcal carriage was significantly associated with pneumococcal pneumonia (nasopharyngeal adjusted odds ratio [aOR] 8.1, 95% confidence interval [CI] 3.8-17.2; oral aOR 5.5, 95% CI 2.1-13.3). All-cause CAP patients ≥65 years had lower odds of nasopharyngeal carriage (aOR 0.47, 95% CI 0.24-0.91) and current smokers had higher odds of oral carriage (aOR 2.69, 95% CI 1.10-6.60). CONCLUSIONS: The association between nasopharyngeal carriage and pneumococcal CAP was strong. Adult carriage and disease from serotypes 8 and 19A may support direct protection of adults with PCV vaccines.

Pneumococcal serotypes and risk factors in adult community-acquired pneumonia 2018-20; a multicentre UK cohort study.

Background: Higher-valency pneumococcal vaccines are anticipated. We aimed to describe serotype distribution and risk factors for vaccine-serotype community-acquired pneumonia (CAP) in the two years pre-SARS-CoV-2 pandemic. Methods: We conducted a prospective cohort study of adults hospitalised with CAP at three UK sites between 2018 and 2020. Pneumococcal serotypes were identified using a 24-valent urinary-antigen assay and blood cultures. Risk factors associated with vaccine-type pneumonia caused by serotypes in the 13-, 15- and 20-valent pneumococcal conjugate vaccines (PCV13, PCV15, PCV20) and 23-valent pneumococcal polysaccharide vaccine (PPV23) were determined from multivariable analysis. Findings: Of 1921 adults hospitalised with CAP, 781 (40.7%, 95% confidence intervals (CI) 38.5-42.9%) had pneumococcal pneumonia. A single PCV13-serotype was detected in 242 (31.0%, 95% CI 27.8-34.3%) pneumococcal CAP patients, mostly serotype 3 (171/242, 70.7%, 95% CI 64.5-76.0%). The additional two PCV15-serotypes were detected in 31 patients (4%, 95% CI 2.8-5.6%), and PCV20-non13-serotypes in 192 (24.6%), with serotype 8 most prevalent (123/192, 64.1%, 95% CI 57.1-70.5%). Compared to PCV13-serotype CAP, people with PCV20-non13 CAP were younger (median age 62 versus 72 years, p < 0.001) and less likely to be male (44% versus 61%, p = 0.01). PPV23-non13-serotypes were found in 252 (32.3%, 95% CI 29.1-35.6%) pneumococcal CAP patients. Interpretation: Despite mature infant pneumococcal programmes, the burden of PCV13-serotype pneumonia remains high in older adults, mainly due to serotype 3. PCV20-non13-serotype pneumonia is more likely in younger people with fewer pneumococcal risk factors. Funding: Unrestricted investigator-initiated research grant from Pfizer, United Kingdom; support from National Institute for Health Research (NIHR) Biomedical Research Centre, Nottingham.

Serotypes associated with the development of pneumococcal para-pneumonic effusion in adults.

Serotypes 1, 3, 7F and 19A are implicated in childhood pneumococcal para-pneumonic effusion (PPE). It is not known whether the same is true for adult PPE. A prospective cohort study was conducted over a 2-year period. Consecutive adults admitted with community-acquired pneumonia (CAP) were studied. Pneumococcal serotype was identified from urine samples using a multiplex immunoassay. Of 920 patients recruited, 366 had pneumococcal CAP; 100 of these had PPE and a serotype was determined in 73 patients. Factors associated with PPE were age, pneumonia severity index score and serotype. Serotypes most associated with PPE were 1 (18 (45%) out of 40), 19A (9 (45%) out of 20) and 3 (8 (40%) out of 20). Serotypes common in childhood PPE were independently associated with adult PPE (adjusted OR 2.3; p = 0.003). Serotypes not included in the 7-valent pneumococcal conjugate vaccine (PCV) were more likely to be associated with PPE (OR 2.1; p = 0.024) compared with those in the vaccine. Serotypes included in PCV-13 were as likely to be associated with PPE as those that are not (OR 0.8; p = 0.301). Serotypes 1, 3, 7F and 19A are independently associated with adult PPE, a similar finding to childhood PPE. Serotype replacement following pneumococcal vaccine implementation may influence the spectrum of clinical disease.