cognitive and psychosocial deficits (Homan, 2016; Larson-Nath & Biank, 2016).
Sudden Infant Death Syndrome
The leading cause of death of infants under the age of 1 is sudden infant death syndrome (SIDS) (Bajanowski & Vennemann, 2017). SIDS is the diagnostic term used to describe the sudden unexpected death of an infant less than 1 year of age that occurs seemingly during sleep and remains unexplained after a thorough investigation, including an autopsy and review of the circumstances of death and the infant’s clinical history (Task Force on Sudden Infant Death Syndrome, 2016).
What causes SIDS? It is believed to be the result of an interaction of factors, including an infant’s biological vulnerability to SIDS coupled with exposure to a trigger or stressor that occurs during a critical period of development (Moon & Task Force on Sudden Infant Death Syndrome, 2016; Spinelli, Collins-Praino, Van Den Heuvel, & Byard, 2017). The first factor is unknown biological vulnerabilities, such as genetic abnormalities and mutations and prematurity, that may place infants at risk for SIDS. For example, a recent 10-year review of hundreds of SIDS cases in Australia confirmed that, although the underlying cause of SIDS remains unknown, mutations and genetic variants likely play a role (Evans, Bagnall, Duflou, & Semsarian, 2013). Second, environmental stressors or events that might trigger SIDS include risks such as having the infant sleep on his or her stomach or side, use of soft bedding or other inappropriate sleep surfaces (including sofas), bed sharing, and exposure to tobacco smoke (Carlin & Moon, 2017). One review of several hundred cases in the United Kingdom found that in over a third of SIDS deaths, infants were co-sleeping with adults at the time of death (Blair, Sidebotham, Berry, Evans, & Fleming, 2006). Finally, there are developmental periods in which infants are most vulnerable to SIDS. Most cases of SIDS occur between the second and fifth months of life (Bajanowski & Vennemann, 2017). Therefore, it is thought that SIDS is most likely to occur when the triple risks—biological vulnerability, triggering events, and critical period of development—converge (Filiano & Kinney, 1994; Spinelli et al., 2017).
Ethnic differences appear in the prevalence of SIDS, with Native Americans and Blacks showing the highest rates of SIDS in the United States, followed by non-Hispanic Whites. Asian American and Hispanic infants show lower rates of SIDS than White infants (Parks, Erck Lambert, & Shapiro-Mendoza, 2017). Ethnic differences in SIDS are likely due to differences in socioeconomic and lifestyle factors associated with SIDS, such as lack of prenatal care, low rates of breastfeeding, maternal smoking, and low maternal age. Cultural practices such as adult–infant bed sharing, providing infants with soft bedding, and placing the sleeping baby in a separate room from caregivers increase SIDS risk (Colson et al., 2013; Parks et al., 2017; Shapiro-Mendoza et al., 2014). However, ethnic differences in SIDS are complex and influenced by context. For example, in one study of infants, those of Mexican American U.S.-born mothers had a 50% greater rate of SIDS than infants of Mexican foreign-born mothers after controlling for factors associated with SIDS, including birthweight, maternal age, education, marital status, prenatal care, and socioeconomic status (Collins, Papacek, Schulte, & Drolet, 2001). Differences in acculturation and associated child care practices likely play a role in influencing SIDS risk, but they are not well understood (Parks et al., 2017).
In the 1990s, SIDS declined dramatically after the American Academy of Pediatrics, based on data from Europe, Australia, and the United States, recommended that infants be placed for sleep in a nonprone position (i.e., a supine position: on their backs) as a strategy to reduce the risk of SIDS (see Figure 4.5) (American Academy of Pediatrics, 1992). Initiated in 1992, the “Back to Sleep” campaign publicized the importance of nonprone sleeping. Between 1992 and 2001, the SIDS rate declined dramatically in the United States and other countries that implemented nonprone/supine sleeping campaigns (Bajanowski & Vennemann, 2017; Bergman, 2015; Moon & Task Force on Sudden Infant Death Syndrome, 2016), consistent with the steady increase in the prevalence of supine sleeping. In addition to placing infants on their backs to sleep, other recommendations for a safe sleep environment include the use of a firm sleep surface, avoidance of soft bedding and infant overheating, and sharing a room with the infant without sharing a bed. Avoid placing infants in sitting devices, such as car seats, strollers, and infant carriers, for routine sleep. Couches and armchairs are extremely dangerous places for infants. SIDS poses grave risks to infants, but the risks can be reduced.
Figure 4.5 Trends in Sudden Unexpected Infant Death (SUID) by Cause, 1990–2015
Source: Centers for Disease Control and Prevention National Center for Health Statistics, National Vital Statistics System, Compressed Mortality File.
Failure to Vaccinate
Failure to vaccinate is a preventable risk to infants’ health. Over the past 60 years, childhood diseases such as measles, mumps, and whooping cough have declined dramatically because of widespread immunization of infants. A vaccine is a small dose of inactive virus that is injected into the body to stimulate the production of antibodies to guard against the disease. Vaccines control infectious diseases that once spread quickly and killed thousands of people. The Centers for Disease Control and Prevention recommends that infants be vaccinated against most vaccine-preventable diseases by the time they are 2 years of age. Currently, 10 vaccines are included in the standard recommendations for children at specific ages between birth and 10 years. Immunization rates vary by vaccine, but overall vaccination coverage in the United States tends to be high. For example, in 2016, 91% of children 19 to 35 months of age were vaccinated for measles, mumps, and rubella (MMR) (National Center for Health Statistics, 2018). However, the percentage of children who have received no vaccines has increased over the past 2 decades, from .3% of 19- to 35-month-old children in 2001 to 1.3% for children born in 2015 (Hill, Elam-Evans, Yankey, Singleton, & Kang, 2018).
Although only a small minority of children are unvaccinated, highly contagious diseases, such as measles, can spread quickly among them. For example, in 2019, nearly 900 cases of measles were reported, largely confined to geographic areas where vaccination is less common (Centers for Disease Control and Prevention, 2019b). The Applying Developmental Science feature examines some of the reasons parents cite for not vaccinating their children.
Applying Developmental Science
Why Don’t Parents Vaccinate?
In 2000, the highly contagious infection measles was declared eliminated from the United States. Yet as of May 2019, 880 cases have been reported, linked to individuals who have not been vaccinated for the disease. Some parents decline or delay vaccinating their children or follow alternative immunization schedules because of medical, religious, philosophical, or socioeconomic reasons (Ventola, 2016). This has caused a resurgence of many infectious diseases.
Vaccination is compulsory for school-age children in the United States, but all states permit exemptions. Currently, exemptions due to medical reasons are allowed in all states, religious grounds in nearly all states, and philosophical objections in 20 states (Bednarczyk, King, Lahijani, & Omer, 2019; Wang, Clymer, Davis-Hayes, & Buttenheim, 2014). It has been estimated that 1% to 3% of children are excused from immunization because of these exemptions, but in some communities the exemption rate is as high as 20% (Ventola, 2016). Even when a low percentage of children are excused from immunization, the risk of disease outbreaks in schools increases.
Vaccines protect children and communities from diseases that once spread quickly and killed thousands of people.
©iStockphoto.com/spukkato
Some researchers argue that, paradoxically, one reason that parents may hesitate to vaccinate their children is the widespread success of immunization (Temoka, 2013). Because of high vaccination rates, most vaccine-preventable diseases have