Immunizations and Vaccine Preventible Diseases


  • Immunizations among Children
  • Immunizations among Infants
  • Measles and Pertussis Incidence
  • Influenza Vaccine among Adults
  • Hospitalization due to Vaccine-preventable Pneumonia and Influenza


  • In 2016-2017, 94.2 percent of children entering daycare and 94.2 percent of children entering kindergarten in San Francisco had all required immunizations.
  • Asian, Pacific Islander and Latino children are more likely to be vaccinated with the complete series than Black/African American and White children. Foreign-born children are less likely to be completely vaccinated than those born in the United States.
  • In 2014, San Francisco again saw a high number of pertussis cases in the setting of a statewide epidemic. The city reports fewer than five cases of measles a year.
  • Influenza and pneumonia disproportionately affect Black/African Americans and people living in the eastern half, and especially the southeastern quadrant, of the city.

What is it?

Routine and safe vaccines are available to protect children, and adults, against 15 infectious diseases— diphtheria, haemophilus influenza type b, hepatitis A, hepatitis B, influenza, measles, mumps, meningococcal disease, pertussis, pneumococcal disease, polio, rotavirus, rubella, tetanus, and varicella [1].

In California, children under 18 are required by law to have immunizations, or a valid medical exemption, to attend school. To enter kindergarten, children must have four doses of the diphtheria-pertussis-tetanus vaccine (DTP or DTaP), three doses of polio vaccine, three doses of hepatitis B vaccine, two doses of measles, mumps, and rubella vaccine (MMR), and one dose of varicella vaccine or evidence of previous varicella disease [2] .The required number of doses for each vaccine for children entering childcare depends upon their age [3]. Seasonal influenza or flu vaccine is not required but recommended for everyone 6 months of age and older. Pneumonia vaccinations are usually only necessary once, although a booster vaccination may be recommended for some individuals, such as the elderly or those with a weakened immune system.

Measles is caused by an extremely contagious virus that spreads through the air when an infected person coughs or sneezes and others inhale the germs. Symptoms begin with a high fever, cough, runny nose and conjunctivitis, followed by a rash that first appears on the face or hairline and spreads downward to the neck, trunk, arms, legs and feet. Infection may lead to encephalitis, pneumonia, or death. The Center for Disease Control (CDC) recommends that children receive the first dose of the measles, mumps, and rubella (MMR) vaccine at 12-15 months of age, and a second dose at 4-6 years.

Pertussis, also known as “whooping cough,” is a respiratory disease caused by the bacterium Bordetella pertussis. Symptoms of pertussis include uncontrollable, violent coughing, which often makes it hard to breathe. Infants with pertussis may stop breathing, a symptom called apnea. Pertussis can be fatal in babies less than one year of age. The CDC recommends that children receive four doses of the diphtheria, tetanus, and pertussis (DTaP) vaccine by 18 months of age, and that pregnant women be vaccinated against pertussis during the third trimester of pregnancy to protect their babies from the infection.

Influenza is a contagious respiratory illness caused by influenza viruses which spread when an infected person coughs or sneezes, or when people touch virus-contaminated surfaces and then touch their mouth or eyes [4]. Pneumonia is an infection or inflammation of the lungs caused by bacteria, viruses, fungi, chemicals, or other agents [5]. Having influenza is itself a risk factor for pneumonia, and while many cases of flu never lead to pneumonia, those that do tend to be more severe and deadly [6]. Older people, young children, pregnant women, persons with weakened immune systems (for example, due to cancer, anti-rejection drugs, corticosteroids or HIV/AIDS), persons with chronic diseases (for example, asthma, chronic obstructive pulmonary disease, or heart disease), and American Indians and Alaskan Natives are at higher risk for influenza and pneumonia infections and serious complications from an infection [7]. Additional risk factors for catching influenza or pneumonia include contact with others who are sick (for example, working in a healthcare setting or living in a group home setting such as a nursing home), and smoking.

For additional data on vaccine-preventable disease in San Francisco, see the hepatitis datasheet.


Why is it important for health?

Vaccine-preventable diseases can be very serious—even deadly—especially for infants and young children. If vaccine coverage levels drop in the population, it is possible that eliminated or rare diseases, such as measles, could become endemic again. High levels of sustained vaccine coverage and rapid public health response are critical for eliminating and controlling vaccine-preventable disease cases and outbreaks [1].

Influenza and pneumonia affect millions of people in the United States every year and together were the ninth leading cause of death in the United States in 2010, and the seventh among those 65-plus years of age. Each year more than 200,000 people are hospitalized as a result of flu complications [4].


What is the status in San Francisco?

Childhood Immunizations The percentage of children entering day care or kindergarten with all recommended vaccinations has been increasing since 2014. In 2016-2017, 94.2% of children entering daycare and 94.2% of children entering kindergarten had all required immunizations in San Francisco. The percentage of children entering childcare or kindergarten with all required immunizations was similar to children statewide (CA childcare: 94.1%, CA kindergarten: 95%) (Figure 1A).
In 2015, as in 2011, 79% of San Francisco’s two year-olds received the recommended four doses of DTaP, three doses of polio, and one or more doses of MMR vaccine (Figure 2A). Data suggests that Asian, Asian Pacific Islander and Latino children were more likely to be vaccinated than Black/African American and White children (Figure 2B). Foreign-born children were less likely to be completely vaccinated than those born in the United States (Figure 2C).

California Senate Bill 277, which eliminates exemption from existing immunization requirements due to personal beliefs, was signed into law in June 2015 and took effect in July 2016 [8]. Senate Bill 277 may affect immunization rates in San Francisco. The proportion of sampled school and childcare children with exemptions to vaccination due to medical contraindications or parental personal beliefs was 3.4% in 2015 (EKRS, 2015).

Pertussis and measles In California, the highest rates of hospitalization due to pertussis were observed among Latino infants younger than one year of age [9]. In 2014, San Francisco again saw high number of pertussis cases in the setting of a statewide epidemic (Figure 3A). However, San Francisco reported fewer infections among infants, possibly due to the recommendation for routine maternal pertussis immunization during the third trimester of pregnancy beginning in late 2012. Measles is very rare in San Francisco, and is not endemic. The city reports fewer than five cases a year. Cases have been linked directly or indirectly to infections acquired in foreign countries.

Influenza Vaccine In 2016, 42.4% of San Franciscans reported they received the annual influenza vaccine (Figure 4A). Vaccination rates among adults 65 years old and older were higher than for younger adults; in 2014-2016 more than 70% of adults over 65 received a vaccine (Figure 4B).

Pneumonia and Influenza Hospitalization The pneumonia and influenza hospitalization and emergency room visit rates were unstable between 2012-2016 with peaks in 2013 and 2015(Figure 5A). Influenza and pneumonia disproportionately affected Black/African Americans and people living in the eastern half, and especially the southeastern quadrant, of the city. Hospitalization rate due to influenza and vaccine-preventable pneumonia was higher among Black/African Americans and emergency room visit rate was higher among Pacific Islanders compared to all other ethnicities (Figure 5B). Zip codes with the highest emergency room visit and hospitalization rates were 94102 (Tenderloin/Civic Center), 94103 (SOMA), and 94124 (Bayview Hunters Point) (Map 5).

What is currently being done in San Francisco to improve health?


Data Sources

SFDPH Communicable Disease Control & Prevention, San Francisco Department of Public Health (SFDPH).
CDPH Immunization Branch. Childcare and kindergarten immunizations., California Department of Public Health (CDPH).
EKRS Expanded Kindergarten Retrospective Survey (EKRS), Communicable Disease Control and Prevention, San Francisco Department of Public Health (SFDPH).
CHIS California Health Interview Survey (CHIS), UCLA Center for Health Policy Research.
OSHPD California Office of Statewide Health Planning and Development (OSHPD).


Methods and Limitations

Childhood Immunizations (EKRS, 2015):

  • Place of birth data was unknown or missing for a portion of the sampled population. It is unclear how this large amount of missing information may have affected the up-to-date comparison based on place of birth.
  • Race/ethnicity was unknown or missing for a portion of the sampled population. Because there is significant variability in vaccination rates between ethnicity groups, basing conclusions on a sample not entirely representative of the ethnicity distributions of San Francisco kindergarteners and transitional kindergarteners could result in a biased estimate of vaccination coverage for the overall population.
  • Exempted children are counted in the denominator when the proportion up-to-date for any vaccination or series is calculated. Consequently, an increase in the frequency of exemptions from vaccination influences the proportion up-to-date downward.

Care should be taken when comparing case counts and rates by year; changes in case definitions and investigation procedures may affect year-to-year comparisons.

Hospitalizations and Emergency Room Visits:
Hospitalization and ER rates measure the number of admissions or visits, not the number of residents who are hospitalized. Admissions records may include multiple admissions by the same person.

​In October 2015, the diagnosis coding standard for Hospitalizations and Emergency Room visits was changed from ICD-9 to ICD-10. Caution should be used in comparing data using the two different standards.

The following ICD-9 and ICD-10 codes were used to identify visits primarily due to vaccine preventable pneumonia and influenza (primary diagnosis only):
ICD-9: 481, 487, 4870, 4871, 4878, 4822, 0551, 4843, 0521
ICD-10: J13, J11, J110, J1100, J1108, J111, J112, J118, J1181, J1182, J1183, J1189, J1189, J14, B052, A3701, B012

Population estimates for rates:

  • State of California, Department of Finance, Race/Hispanics Population with Age and Gender Detail, 2000–2010. Sacramento, California, September 2012.
  • California Department of Finance. Demographic Research Unit. 2018. State and county population projections 2010-2060 [computer file]. Sacramento: California Department of Finance. February 2017.

Standard Population for age adjustment:

  • Population Projections of the United States by Age, Sex, Race, and Hispanic Origin: 1995 to 2050. U.S. Department of Commerce, Economics and Statistics Administration, BUREAU OF THE CENSUS

Statistical instability: Statistically unstable estimates are not shown in this document. Statistical instability may arise from:
…few respondents to a survey,
…small population sizes, or
…small numbers of affected individuals.
Statistical instability indicates a lack of confidence in an estimates ability to accurately and reliably represent the population. Due to statistical instability, estimates are not available for all age, gender, ethnicity, or other groups.


References[1] Centers for Disease Control and Prevention (CDC). 2017. Immunization schedules for infants and children in easy-to-read formats.
[2] California Department of Public Health (CDPH). 2017. Guide to immunization required for school entry.
[3] California Department of Public Health (CDPH). 2017. Guide to immunization required for child care.
[4] Centers for Disease Control and Prevention. 2016. Key facts about influenza (flu) and flu vaccine.
[5] American Lung Association. What causes pneumonia. 2016.
[6] American Lung Association. What is the connection between influenza and pneumonia? 2016.
[7] Centers for Disease Control and Prevention. People at high risk of developing flu–related complications., 2016.
[8] California Legislative Information. Senate bill 277, chapter 35., 2015.
[9] California Department of Public Health. Pertussis summary reports.