Protecting Newborns From Pertussis

The Challenge of Complete Cocooning

Pascal Urwyler; Ulrich Heininger

BMC Infect Dis. 2014;14(397)

Abstract and Introduction

Abstract

Background: An increase of pertussis cases, especially in young infants and adolescents, has been noted in various countries. Whooping cough is most serious in neonates and young infants in whom it may cause serious complications such as cyanosis, apnoea, pneumonia, encephalopathy and death. To protect newborns and infants too young to be fully immunized, immunization of close contact persons has been proposed ("cocoon strategy") and implemented in several countries, including Switzerland in 2011. The goal of this study was to assess knowledge about pertussis among parents of newborns and acceptance, practicability and implementation of the recently recommended pertussis cocoon strategy in Switzerland.

Methods: We performed a cross sectional survey among all parents of newborns born between May and September 2012 and 2013 in Basel city and country. Regional statistical offices provided family addresses after approval by the ethical and data protection committees. A standardized questionnaire with detailed instructions was sent to all eligible families. For statistical analyses, independent proportions were compared by Pearson's chi-squared test.

Results: Of 3546 eligible parents, 884 (25%) participated. All three questions exploring pertussis knowledge were answered correctly by 37% of parents; 25% gave two correct answers, 22% gave one correct answer and in the remaining 16% no answer was correct. Pertussis immunization as part of cocooning was recommended to 20% and 37% of mothers and 14% and 32% of fathers in the 2012 and 2013 study cohorts, respectively. Principal advisors for cocooning were pediatricians (66%) followed by gynecologists/obstetricians (12%) and general practitioners (5%). When recommended, 64% of mothers and 59% of fathers accepted pertussis immunization. The majority of vaccinations were administered in the perinatal period and within 2 months of the child's birth. However, cocooning remained incomplete in 93% of families and in most families <50% of close contacts received pertussis vaccination.

Conclusions: Implementation of cocooning for protecting newborns from pertussis is challenging and usually remains incomplete. Pertussis immunization rates among close contacts of newborns need to be improved. Ideally, all healthcare providers involved in family planning, pregnancy and child birth should recommend cocooning. Pertussis immunization of pregnant women is an additional measure for optimal protection of newborns and should be promoted.

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Abstract and Introduction
Background
Methods
Results
Discussion
Conclusions
References

Table 1. General characteristics of study cohorts
	Birth year 2012 N (%)	Birth year 2013 N (%)	Total N (%)
Newborn	426 (100)	458 (100)	884 (100)
Sex, known	426 (100)	457 (99.7)	883 (99.9)
Female	203 (48)	195 (43)	398 (45)
Nationality, known	426 (100)	455 (99.3)	881 (99.7)
Swiss^a	344 (81)	373 (81)	717 (81)
Other	82 (19)	82 (18)	164 (19)
Maternity clinic, known	426 (100)	455 (99.3)	881 (99.7)
Hospital A	178 (42)	192 (42)	370 (42)
Hospital B	113 (27)	125 (27)	238 (27)
Hospital C	93 (22)	108 (24)	201 (23)
Other	42 (10)	30 (7)	72 (8)
Mothers	426 (100)	458 (100)	884 (100)
Age (in years), known	418 (98)	439 (96)	857 (97)
Mean/Median	33/33	33/33	33/33
IQR/Range	30–36/17–46	30–36/20–47	30–36/17–47
Educational level, known ^b	421 (99)	451 (98)	872 (99)
Compulsory school (ISCED 2)	21 (5)	17 (4)	38 (4)
Apprenticeship (ISCED 3)	130 (31)	147 (32)	277 (31)
Higher education (ISCED 4)	270 (63)	287 (63)	557 (63)
Fathers	424 (100)	453 (100)	877 (100)
Age (in years), known	402 (95)	412 (91)	816 (93)
Mean/Median	36/35	36/35	36/35
IQR/Range	32–40/21–56	30–36/20–77	32–39/20–77
Educational level, known ^b	418 (99)	442 (98)	860 (98)
Compulsory school (ISCED 2)	19 (4)	23 (5)	42 (5)
Apprenticeship (ISCED 3)	149 (35)	148 (33)	297 (34)
Higher education (ISCED 4)	250 (59)	271 (60)	521 (59)
Cocoon size
Siblings ^c	212 (100)	259 (100)	471 (100)
Mean/Range^d	0.5/0–4	0.57/0–4	0.5/0–4
Other close contact persons ^e	663 (100)	758 (100)	1421 (100)
Mean/Range^d	1.6/0–7	1.7/0–5	1.6/0–7
Total (including parents)	1725 (100)	1928 (100)	3653 (100)
Mean/Range^d	4.0/1–11	4.2/1–9	4.1/1–11

^aIncluding newborns with multiple citizenships (Swiss plus other).
^bInternational Standard Classification of Education Levels.
^cTwin siblings and subsequently born siblings not included as these were not relevant for cocooning at time of birth of study infant.
^dNumber of close contacts per newborn.
^eOther than parents or siblings.

Table 2. Parental knowledge about pertussis
Questionnaire filled in by (N)	Birth year 2012						Birth year 2013						Overall Total 884
Questionnaire filled in by (N)	Mother 301	Father 27	both 95	other 1	unknown 2	Subtotal 426	Mother 310	Father 32	both 111	other 1	Unknown 4	Subtotal 458	Overall Total 884
Question 1 ^a
N (%) correct answers	144 (48)	8 (30)	38 (40)	0 (0)	0 (0)	190 (45)	164 (53)	11 (34)	71 (64)	0 (0)	4 (100)	250 (55)	440 (50)
Question 2 ^b
N (%) correct answers	214 (71)	20 (74)	60 (63)	1 (100)	0 (0)	295 (69)	227 (73)	17 (53)	77 (69)	1 (100)	4 (100)	326 (71)	621 (70)
Question 3 ^c
N (%) correct answers	189 (63)	15 (56)	52 (55)	1 (100)	1 (50)	258 (61)	205 (66)	18 (56)	77 (69)	1 (100)	4 (100)	305 (67)	563 (64)

^aHow well are newborns protected against pertussis?
^bFor which age group is pertussis most dangerous?
^cWhat is the most common source of infection for pertussis in newborn?

Table 3. Parental pertussis immunization by time relation to child's birth and by advisor, 2012 and 2013 study cohorts combined
Advisor	<10 years before birth			During month of birth			<6 months after birth			Overall Total N (%)
Advisor	Mother N	Father N	Subtotal N(%)	Mother N	Father N	Subtotal N(%)	Mother N	Father N	Subtotal N(%)	Overall Total N (%)
Pediatrician	6	10	16 (10)	18	12	30 (18)	65	52	117 (72)	163 (66)
Gynecologist/obstetrician	13	4	17 (57)	3	1	4 (13)	6	3	9 (30)	30 (12)
General practitioner	5	1	6 (50)	1	1	2 (17)	2	2	4 (33)	12 (5)
Travel medicine clinic	2	5	7 (88)	0	1	1 (13)	0	0	0 (0)	8 (3)
Spouse/partner	0	1	1 (25)	0	3	3 (75)	0	0	0 (0)	4 (2)
Employer	2	1	3 (75)	0	0	0 (0)	1	0	1 (25)	4 (2)
Other ^a	4	0	4 (67)	1	0	1 (17)	1	0	1 (17)	6 (2)
>1 of the above	2	1	3 (16)	4	3	7 (37)	6	3	9 (47)	19 (8)
Total	34	23	57 (23)	27	21	48 (20)	81	60	141 (57)	246 (100)^b

^aRecommendation from internet (N = 2)/from media (N = 1), family member (N = 2), midwife (N = 1).
^bDifferent Total compared to Figure 3; advisor unknown in 35 mothers and 20 fathers and 11 parents received immunization >6 months after birth of child.

Table 4. Parental pertussis immunization rate following recommendation by advisor, 2012 and 2013 study cohorts combined
Advisor^a	Mothers N immunization received/N immunization recommended (%)	Fathers N immunization received/N immunization recommended (%)	Overall N immunization received/N immunization recommended (%)
Pediatrician	99/162 (61)	77/140 (55)	176/302 (58)
Gynecologist/obstetrician	22/34 (65)	12/19 (63)	34/53 (64)
GP	10/12 (83)	4/7 (57)	14/19 (74)
Travel medicine clinic	2/4 (50)	6/8 (75)	8/12 (67)
Midwife	5/9 (56)	2/2 (100)	7/11 (64)
Partner	0/0 (0)	7/9 (78)	7/9 (78)
Employer	5/6 (83)	1/1 (100)	6/7 (86)
Internet	4/5 (80)	1/1 (100)	5/6 (83)
Unknown	1/3 (33)	1/3 (33)	2/6 (33)
Other ^b	4/10 (40)	1/5 (20)	5/15 (33)
>1 of the above	12/13 (92)	7/8 (88)	19/21 (90)
Total	164/258 (64)	119/203 (59)	283/461 (61)

^aMentioned if N total > 5.
^bFriend (N = 5), children's hospital (N = 4), family (N = 3), recommendation from media (N = 2) or general health promotion (N = 1).

Table 5. Parental reasons for lack of pertussis immunization despite recommendation, 2012 and 2013 study cohorts
Parents not receiving immunization despite recommendation (N)^a	Birth year 2012			Birth year 2013			Overall Total (178) N (%)
	Mothers (27) N (%)	Fathers (25) N (%)	Subtotal (52) N (%)	Mothers (67) N (%)	Fathers (59) N (%)	Subtotal (126) N (%)	Overall Total (178) N (%)
Solicited reasons ^b
No opportunity	12 (44)	6 (24)	18 (35)	24 (36)	22 (37)	46 (37)	64 (36)
Forgotten	7 (26)	10 (40)	17 (33)	14 (21)	15 (25)	29 (23)	46 (26)
Perceived side effects	4 (15)	1 (4)	5 (10)	11 (16)	6 (10)	17 (13)	22 (12)
Considered not important	2 (7)	4 (16)	6 (12)	5 (7)	8 (14)	13 (10)	19 (11)
Doubts about effectiveness	2 (7)	1 (4)	3 (6)	6 (9)	6 (10)	12 (10)	15 (8)
Cost	2 (7)	1 (4)	3 (6)	1 (1)	1 (2)	2 (2)	5 (3)
Religious beliefs	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)
Unsolicited reasons ^b
Believed to be up to date^c	4 (15)	2 (8)	6 (12)	9 (13)	4 (7)	13 (10)	19 (11)
Recommendation came too late	0 (0)	0 (0)	0 (0)	5 (7)	3 (5)	8 (6)	8 (4)
Recommendation not known	3 (11)	0 (0)	3 (6)	1 (1)	2 (3)	3 (2)	6 (3)
Immunization discouraged by physician	1 (4)	1 (4)	2 (4)	3 (4)	1 (2)	4 (3)	6 (3)
Immunization considered unnecessary	1 (4)	1 (4)	2 (4)	2 (3)	1 (2)	3 (2)	5 (3)
Sceptical about immunizations	0 (0)	0 (0)	0 (0)	1 (1)	2 (3)	3 (2)	3 (2)
Recent tetanus immunization	0 (0)	0 (0)	0 (0)	4 (6)	1 (2)	5 (4)	5 (3)
Risk of pertussis considered to be low	0 (0)	0 (0)	0 (0)	3 (4)	1 (2)	4 (3)	4 (2)
Positive history of pertussis disease	0 (0)	1 (4)	1 (2)	1 (1)	1 (2)	2 (2)	3 (2)
Breastfeeding	2 (7)	N/A	2 (4)	1 (1)	N/A	1 (0.8)	N/A
Other	2 (7)	3 (12)	5 (10)	6 (9)	4 (7)	10 (8)	13 (7)

^a27/67 mothers (2012/2013) and 24/53 fathers (2012/2013) indicated reasons.
^bOne or more reasons could be given.
^cOf which 9 parents (6 mothers and 3 fathers) actually were up to date.

Table 6. Pertussis immunization in close contact persons of newborns – 2012 and 2013 study cohorts
Contact person	Birth year 2012		Birth year 2013		Total
Contact person	N	N up to date (%)	N total	N up to date (%)	N total	N up to date (%)
Siblings	212	171 (81)	259	201 (78)	471	372 (79)
Grandmothers	324	12 (4)	358	38 (11)	682	50 (7)
Grandfathers	224	9 (4)	270	29 (11)	494	38 (8)
Nanny/daycare	48	0 (0)	30	1 (3)	78	1 (1)
Aunt	25	5 (20)	36	3 (8)	61	8 (13)
Uncle	16	3 (19)	24	4 (17)	40	7 (18)
Other ^a	26	0 (0)	40	1 (3)^b	66	1 (2)

^aGodmother (N = 17), Godfather (N = 7), Great-grandmother (N = 4), Great-grandfather (N = 1), Great-aunt (N = 2), Friend of family (N = 5), Cousin (N = 7), Niece (N = 1), Other children at daycare (N = 3), Mother's cousin (N = 1), not specified (N = 18).
^bGodfather.