Author, date and country | Patient group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
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Pourcyrous et al 2007 USA | 239 preterm infants in a neonatal unit (mean gestation age 28 weeks) receiving their first vaccination - either (i) a single vaccination [DTaP, Hib, IPV, HBV or PCV7] and the remainder 3 days later or (ii) two or more vaccinations simultaneously with the remainder 3 days later. | Prospective observational | Serum CRP before immunisation and 12 hourly post immunisation for 36 hours. | 85 % of infants receiving multiple vaccinations had a CRP > 16 mg/L (max 108). CRP also rose in infants receiving DTaP (24%), PCV7 (54%) and Hib (70%), but not with IPV or HBV. | Multiple subgroups mean each has relatively small number of subjects. |
Korczowski 2004 Poland | 17 infants (mean age 20 weeks) presenting to an emergency department with vaccine-associated adverse reactions (fever; local swelling; seizure or hypotonic hyporesponsiveness; persistent crying; vomiting) | Retrospective observational | Serum CRP at time of presentation. | CRP raised (>5 mg/L) in 13 cases (mean 21 +/- 5mg/L). 9 infants admitted to hospital; lumbar puncture performed in 4 infants; intravenous antibiotics started in 2. Culture results all negative. | Small study group of non-premature infants. Only representative of infants attending with adverse reactions, although this group may be of clinical importance. Various combinations of vaccines had been given (6 in total). |
Balkundi et al 1994 UK | 12 infants in a neonatal unit given DTP and Hib immunisation | Prospective observational | CRP level for 48 hours post immunisation | Median CRP value < 4 mg/L pre-immunisation, rising to 10.4 mg/L 24 hours post-immunisation and 18 mg/L (range 4.2 - 48.g mg/L) 48 hours postimmunisation | Small study group. Wide range of CRP responses. One (included) infant screened for infection during study; it is unclear whether this infant was septic, if so this may have affected the results. |
Pourcyrous et al 1998 USA | (i) 79 premature infants (mean gestational age at birth 28 weeks) in a neonatal unit receiving first (79) or second (2) set of immunisations (DTwP, Hib, HBV +/- IPV) (ii) 10 further premature infants (mean gestational age at birth 27 weeks) receiving DTaP with Hib, HBV and IPV given two days later. | Prospective observational | Serum CRP before immunisation and 12 hourly post immunisation until CRP normal. | (i) Following immunisation CRP rose from < 10 mg/L to a maximum (mean) of 40 +/- 20 mg/L at 32 +/- 9 hours after immunisation in 78 of the 79 infants (the remaining infant later proved to have a T-cell disorder). CRP normalised at a mean of 82 +/- 27 hours. Two infants received antibiotics (cultures negative). | The two differences between the study groups (DTwP cf DTaP and concurrent cf delayed) make it difficult to interpret the results. Small second study group. |
Ellison et al 2005 Australia | 48 preterm infants (mean gestational age at birth 26.4 weeks) receiving first vaccination (either DTaP, Hib, HepB and IPV or DTaP, Hib and Hep B) in a neonatal unit. | Retrospective observational | Adverse events during the 48 hours pre-immunisation and post-immunisation. | Infants were signficantly more likely to have a temperature > 48 degrees centigrade post-immunisation. 4 infants underwent septic work up post-immunisation (either due to increased oxygen requirement or apnoea requiring stimulation). In each CRP was increased (range 15 to 58 mg/L). In each cultures were negative. | Retrospective study. Small study group. CRP measured only in infants with worrying adverse reactions. |