← Master Index· Section 8 · Infectious Diseases · Chapter 52

Vaccines, Toxoids, and Other Immunobiologics

VaccinesImmunobiologicsACIPImmunizations

30-Second Snapshot

What this chapter is:the catch-all for vaccines, toxoids, and immunoglobulins that don't get a full chapter of their own, plus the mechanical rules that govern immunization practice generally. Influenza, COVID-19, and hepatitis vaccines live in their own chapters (43, 37, 25) and aren't repeated here.

The core problem:almost every rule in this chapter, who can get what, when, and how far apart, traces back to a single fact about each product: is it live or is it not? That one classification decides pregnancy safety, immunocompromise safety, and spacing from other vaccines.

What you do about it:know the type (live, inactivated, toxoid, conjugate, polysaccharide, recombinant) for each vaccine below, know the primary series and booster timing for the higher-yield ones, and know the exceptions the exam loves (the HIV/measles exception, the leukemia-off-chemo exception, wound-specific tetanus prophylaxis, PCV-then-PPSV23 sequencing).

The organizing mental model

Live vaccines replicate transiently inside the patient, mimicking a mild version of the actual infection.That's what makes the immune response strong and durable, and it's exactly why they're off-limits in pregnancy and significant immunosuppression, and why two live vaccines can't be stacked unless given the same day. Everything else on this chapter's list, toxoids, conjugates, polysaccharides, recombinant proteins, inactivated whole virus, can't replicate, so it's safe in essentially every population, it just usually needs more doses or a booster to get there since there's no mimicked infection reinforcing it.

The Vaccine & Immunobiologic Categories

Before memorizing a single schedule, sort every product in this chapter into one of these buckets. The bucket predicts the safety profile.

CategoryHow it worksExamples hereImmune response
Live attenuatedWeakened organism still replicates transiently, mimics real infectionMMR, varicellaStrong, durable, often lifelong after full series
ToxoidInactivated bacterial toxin, not the organism itselfDiphtheria toxoid, tetanus toxoidAntitoxin antibody; needs periodic boosters since no ongoing infection is mimicked
Polysaccharide conjugateBacterial capsule sugar chemically linked to a carrier proteinHib, PCV13/15/20, MenACWYT-cell dependent, works in infants, builds immune memory, boosts on re-exposure
Plain polysaccharideBacterial capsule sugar alone, no carrier proteinPPSV23T-cell independent, poor response under age 2, no memory or booster effect
Recombinant / subunitLab-produced protein antigen, no live organism involvedHPV, recombinant zoster (RZV)Inactivated-type safety profile, despite RZV's shingles-sounding name
Inactivated whole virusKilled virus, cannot replicateIPV (injectable polio)Safe across immunocompromise; primary series plus boosters
ImmunoglobulinPooled or targeted antibody, passive immunity, not activeTIg, IGIM, IGIV, RhoD IgImmediate but temporary protection; generates no memory
The exam trap

Zoster vaccine is not live.Shingles comes from reactivated varicella-zoster virus, so it's tempting to assume the vaccine that prevents it is also live, the way the varicella vaccine itself is. The currently recommended recombinant zoster vaccine (RZV) is an adjuvanted protein subunit product, which is exactly why it's usable in populations where MMR and varicella would be contraindicated.

How Immunity Actually Forms

An adjuvantis a chemical additive that provokes a strong but short-lived local inflammatory response. That inflammation is what recruits immune cells to the injection site and amplifies the response to the antigen riding along with it, which is exactly why adjuvanted products (like RZV) tend to cause more injection-site soreness than plain ones.

The conjugate-versus-plain-polysaccharide distinction above is worth sitting with, because it explains a real clinical decision. A bare polysaccharide antigen (PPSV23) only activates B cells directly, a T-cell-independent response, which infant immune systems are bad at mounting and which doesn't leave behind memory cells. Attach that same sugar to a carrier protein (any of the conjugate vaccines) and T cells get involved, which is what lets a 2-month-old respond to Hib or PCV, and what lets a booster dose actually boost.

Why this matters clinically

This is the entire reason PCV and PPSV23 aren't interchangeable in adults with immunocompromising conditions (see the pneumococcal section below). The conjugate vaccine primes a durable, boostable response; the polysaccharide vaccine broadens serotype coverage but doesn't prime memory the same way. Give them in the right order and the right vaccine does the job it's actually good at.

The Coadministration & Timing Rules

These rules apply across every vaccine in the schedule, not just the ones in this chapter, and they're some of the highest-yield, least-memorized content in immunization pharmacy.

CASE 1

Inactivated + inactivated

No spacing required. Same visit or any interval.
CASE 2

Inactivated + live

No spacing required. Same visit or any interval.
CASE 3

Live + live, same day

Fine to give both today (this is how MMR itself works, three live components at once).
CASE 4

Live + live, different days

Must be separated by at least 4 weeks.
The only case that requires spacing

Read that grid again: three of the four combinations need zero spacing.The 4-week rule only bites when you have two differentlive vaccines given on two differentdays. That's a much narrower rule than most students assume, and a favorite place for exam writers to test whether you actually know it or just remember "vaccines need spacing" as a vague rule.

Pregnancy and postpartum

Live vaccines (rubella, varicella, and by extension MMR) are deferred until pregnancy is over. If a patient lacks documented immunity, the standard approach is to vaccinate before hospital discharge postpartum. RhoD Ig doesn't block this, live vaccines can be given without regard to RhoD Ig timing in the postpartum period, so a Rho(D)-negative mother can get her RhoD Ig injection and her MMR/varicella catch-up in the same visit. Tdap is also recommended for any new mother who hasn't previously received it, since household contacts, including mom, are a frequent source of pertussis exposure for a newborn too young to be fully vaccinated.

Who Can (and Can't) Get Live Vaccines

This is the population-by-population screen you actually run before pulling a live vaccine out of the fridge.

PopulationLive vaccinesInactivated / toxoid
PregnancyContraindicated, defer to postpartumFine (Tdap actively recommended each pregnancy)
Chronic pulmonary, renal, hepatic, or metabolic disease, not on immunosuppressantsFineFine
Active malignant diseaseContraindicated exception belowFine
Leukemia, off chemo ≥3 monthsMay receive live virus vaccinesFine
High-dose corticosteroids, or any course >2 weeksWait ≥1 month after stopping before live vaccinationFine
HIV infectionSuboptimal response, but MMR still given exceptionFine, though response may be suboptimal too
Transplant candidates/recipientsImmunize beforetransplant when possible; generally not given afterCase-by-case
Severely immunocompromised(general)Contraindicated, no exceptionsFine
The default rule

Severely immunocompromised patients do not get live vaccines.If you remember nothing else from this table, remember that one, then layer the exceptions on top of it.

The near-miss pair students mix up

HIV is technically an immunocompromising condition, yet HIV-positive children without evidence of measles immunity still get MMR.The reasoning isn't that HIV makes the vaccine safer, it's that measles infection is disproportionately severe and often fatal in untreated or poorly controlled HIV, so the calculus flips: the risk of notvaccinating outweighs the theoretical vaccine risk. Contrast that with rubella and mumps vaccine alone, which stay contraindicated in immunosuppressed patients generally. It's specifically the measles-containing combination, driven by measles severity, that gets the carve-out.

A case worth remembering

A patient who becomes newly immunosuppressed (say, starting a biologic or chemo) and has already completed Tdap, Hep B series, MMR, MenB, and HPV needs a fresh look at her chart: anything liveshe hasn't yet completed (MMR boosters, varicella if not immune) should ideally be finished beforeimmunosuppression starts, not after. Once she's immunosuppressed, those become contraindicated until her status changes, while toxoid and inactivated products (Tdap, Hep B, HPV, MenB) remain fair game on schedule.

Diphtheria, Tetanus & Pertussis

Diphtheria toxoid

Comes in two strengths: D(pediatric, full-strength) for children under 7, and d(adult, reduced-strength) for everyone older, because adults react more to the full pediatric dose. D is given as part of DTaP at 2, 4, and 6 months, then boosted at 15–18 months and again at 4–6 years. Unvaccinated adults need a three-dose series: first two doses at least 4 weeks apart, third dose 6–12 months after the second, with one dose of that series being Tdaprather than plain Td. Boosters (Td or Tdap) repeat every 10 years. Expect mild-to-moderate injection site tenderness, erythema, and induration.

Tetanus toxoid and tetanus immunoglobulin

Primary series in kids rides along with DTaP: 0.5 mL doses at 2, 4, 6, and 15–18 months. Previously unimmunized people age 7 and up get three 0.5 mL IM doses of Td, the first two 1–2 months apart, the third 6–12 months after the second, then boosters every 10 years.

Vaccination historyClean, minor woundAll other wounds
Td/TdapTIgTd/TdapTIg
Unknown or <3 prior dosesYesNoYesYes
≥3 prior dosesNo*NoNo†No

*Give a dose if >10 years since the last one. †Give a dose if >5 years since the last one. A single Tdap dose (rather than plain Td) should be used for whichever dose comes next in anyone over age 10.

The wound table, decoded

TIg is only ever for the unknown-or-under-3-doses column, and only ever for the dirty/major-wound row.A fully immunized patient (≥3 documented doses) never needs TIg regardless of the wound, they just might need a Td/Tdap booster if it's been long enough. This is a classic "count the doses, check the clock, check the wound" three-variable question.

TIg dosing is two very different numbers depending on the indication.Prophylaxis after a wound in an under-immunized patient is 250–500 units IM. Treatment of actual clinical tetanus is 3,000–6,000 units IM, roughly an order of magnitude higher, given as a single dose. When TIg and tetanus toxoid are both indicated, give them at separate injection sites.

Pertussis

Acellular pertussis rides along with diphtheria and tetanus as DTaP. Same primary series (2, 4, 6, 15–18 months), booster at 4–6 years, one adolescent acellular-pertussis dose between ages 11–18, and a single adult Tdap dose for everyone else. Tdap is specifically recommended in the late second or third trimester of every pregnancy, not just the first, because the goal is maternal antibody transfer that protects the newborn until they're old enough for their own doses. Close contacts and caregivers of a new infant should also get Tdap if not already up to date, the "cocoon" strategy.

Systemic reactions like moderate fever hit 3–5% of pertussis-vaccine recipients. Rarely: high fever, febrile seizures, persistent crying spells, and hypotonic-hyporesponsive episodes.

Measles, Mumps, Rubella & Varicella

These four ride together conceptually: all live, all pediatric, all built around the same 12–15 month primary dose plus a 4–6 year booster, and all sharing the pregnancy/immunosuppression contraindication discussed above.

VaccinePrimary doseBoosterNotable rule
Measles(as MMR)12–15 months4–6 yearsIndicated in anyone born after 1956 without documented immunity; HIV exception applies (see above)
Mumps(as MMR)12–15 monthsBefore elementary school entry2 doses recommended for school-age kids, international travelers, post-high-school students, and healthcare workers born after 1956; postexposure vaccination gives no benefit
Rubella(as MMR)12–15 months4–6 yearsAll people of childbearing potential need documented immunity or a dose; not linked to congenital rubella syndrome but still contraindicated in pregnancy
Varicella12–15 months4–6 yearsCatch-up for anyone lacking immunity: 2 doses, 4–8 weeks apart
The "born after 1956" line

Anyone born after 1956without documented wild-type infection (by history or antibody titer) needs measles vaccination. The flip side, commonly tested as "presumed immune," is that most people born in or before 1956 lived through widespread natural measles circulation and don't need it. Know the cutoff, not just the concept.

Worth knowing

Rubella vaccine specifically comes with a contraception counseling point: advise avoiding pregnancy for 4 weeks after vaccination, even though real-world surveillance hasn't tied the vaccine to congenital rubella syndrome. It's a precautionary window, not a proven-harm window, but it's still the guideline.

Varicella has its own immune-deficiency nuance:children with humoralimmune deficiencies (antibody production problems) may still be immunized, they aren't lumped in with combined or cellular immunodeficiency, which remains an absolute contraindication. That's a fine distinction worth flagging since "immune deficiency" gets treated as one bucket far too often.

Hib, HPV, Meningococcal, Pneumococcal & Polio

Haemophilus influenzae type b (Hib)

Conjugate vaccine, routine for all infants and children under 5. Primary series: 0.5 mL IM at 2, 4, and 6 months, booster at 12–15 months. Catch-up is age-dependent: unvaccinated infants 7–11 months get two doses 4 weeks apart plus a booster at 12–15 months (at least 8 weeks after dose 2); unvaccinated children 12–14 months get two doses 2 months apart; a child older than 15 months just needs a single dose of any of the four conjugate products.

HPV

ACIP recommends HPV vaccination ages 9–26, with routine timing at 11–12 and catch-up through 26. The dose count depends entirely on the age the series starts:starting at 9–14 years gets a 2-dose series 6 months apart; starting at 15 or older gets the full 3-dose series at 0, 1–2, and 6 months. Ages 27–45 aren't routine but are shared clinical decision-making, using the 3-dose schedule. Tolerability is good, injection site reactions, headache, and fatigue occur at rates similar to placebo.

Why fewer doses under 15

This isn't a convenience shortcut, younger adolescent immune systems mount a stronger response per dose, so ACIP determined 2 doses in that age band produces comparable immunogenicity to 3 doses later. If a patient starts the 2-dose series at 14 but turns 15 before finishing, current guidance still allows completing the 2-dose schedule they started (know that the age-at-startis what locks in the schedule).

Meningococcal

Two MenACWYconjugate products, Menactra (licensed 9 months–55 years) and Menveo (licensed 2 months–55 years). Routine dosing is all children at 11–12 years, with a booster at 16. High-risk patients get reimmunized every 5 years. Separately, two MenBvaccines (Trumenba, Bexsero) exist and are reserved for individuals at high risk of invasive meningococcal disease, they are not part of the routine adolescent schedule.

MenACWY ≠ MenB

These are two separate vaccines targeting different serogroups, given on completely different schedules to different patient populations. A patient who got their routine 11-12/16-year MenACWY series has notbeen vaccinated against serogroup B disease unless they separately qualify for and receive a MenB product.

Pneumococcal

Four preparations exist, PCV13, PCV15, PCV20, and PPSV23, and they are not interchangeable. For adults with an immunocompromising condition: give PCV20 or PCV15, then PPSV23 eight weeks later. If the patient already received one or more PPSV23 doses, either PCV15 or PCV20 can still be given, spaced at least a year from the last PPSV23 dose. If someone was already PCV13-immunized, don't repeat a conjugate vaccine.

Indications for PCV20/15 → PPSV23, adults ≥19
Functional or anatomic asplenia · sickle cell disease or other hemoglobinopathies · congenital or acquired immunodeficiency · HIV infection · chronic renal failure or nephrotic syndrome · leukemia, lymphoma, Hodgkin lymphoma · generalized malignancy · immunosuppressive drug therapy including long-term systemic corticosteroids or radiation · solid organ transplant · multiple myeloma · high-risk conditions (chronic heart, liver, or lung disease, diabetes, alcoholism, smoking)

Pediatric dosing: PCV13/15 as 0.5 mL IM at 2, 4, and 6 months plus a dose at 12–15 months. Kids 6–18 years with sickle cell disease, splenic dysfunction, HIV, immunocompromise, a cochlear implant, or a CSF leak get a single supplemental PCV13/15 dose.

Poliovirus

Two trivalent products: inactivated (IPV) and live-attenuated oral (OPV). IPV is the US standard, given at 2, 4, 6–18 months, and 4–6 years, with primary immunization recommended through age 18. OPV is reserved for regions where wild poliovirus still circulates. Allergy to any IPV component, including streptomycin, polymyxin B, or neomycin, is a contraindication, worth knowing since those are manufacturing residuals, not the antigen itself.

Zoster (Shingles) Vaccine

The recombinant zoster vaccine (RZV) is adjuvanted and, as established above, not live. ACIP recommends it for immunocompetent adults 50 years and older, given as a 2-dose series at 0 and 2–6 months. It's 91% effectiveat preventing zoster. Tolerability runs high: about 80%of recipients report injection-site pain, and 9%report reactions significant enough to interfere with normal activities, worth counseling proactively so patients don't skip dose 2.

Why this vaccine is also a nerve-pain prevention strategy

Post-herpetic neuralgia (PHN), the burning, allodynic pain that can persist for months to years after a shingles outbreak, is the most common long-term complication of herpes zoster and is notoriously hard to treat once established (TCAs, gabapentinoids, lidocaine patches, multimodal therapy, often for the long haul). The predecessor live zoster vaccine (Zostavax) was shown to reduce shingles incidence by roughly 51%and PHN incidence by roughly 66%in older adults, and even among patients who still developed PHN, vaccination reduced illness burden by about 61%. RZV's 91%efficacy against zoster itself is a substantial upgrade over that older live product, which is exactly why counseling for RZV should frame it as PHN prevention, not just "avoiding a rash."

Immunoglobulins & Rho(D) Immunoglobulin

Immunoglobulin (Ig) products are sterile, antibody-containing solutions purified from human plasma, available as intramuscular (IGIM) or intravenous (IGIV) preparations. Because they deliver ready-made antibody rather than provoking the patient's own immune system, protection is immediate but temporary, and no immune memory is generated.

IGIM dosing by indication

IndicationDose
Primary immunodeficiency states1.2 mL/kg IM, then 0.6 mL/kg every 2–4 weeks
Hepatitis A exposure0.02 mL/kg IM within 2 weeks, if age <1 or >39 years
Hepatitis A prophylaxis, exposure <3 months0.02 mL/kg IM
Hepatitis A prophylaxis, exposure up to 5 months0.06 mL/kg IM
Hepatitis B exposure0.06 mL/kg (HBIG preferred for known exposures)
Measles exposure0.5 mL/kg IM (max 15 mL), as soon as possible

IGIV indications

Primary immunodeficiency states (both antibody and combined deficiencies) · idiopathic thrombocytopenia · chronic lymphocytic leukemia with a serious bacterial infection · Kawasaki disease · pediatric HIV infection · allogeneic bone marrow transplant · chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy · kidney transplant recipients with high antibody titers or an ABO-incompatible donor.

Rho(D) immunoglobulin (RhoD Ig / RDIg)

RDIg suppresses formation of anti-Rho(D) antibody in Rho(D)-negative, Du-negativewomen exposed to Rho(D)-positive blood, preventing erythroblastosis fetalis in a future pregnancy with a Rho(D)-positive fetus. Given IM within 72 hours of a full-term delivery, it drops the rate of active antibody formation from 1% down to 0.2%. It's also used after inadvertent transfusion of Rho(D)-positive blood in a premenopausal Rho(D)-negative woman, and after abortion, miscarriage, amniocentesis, or abdominal trauma.

The pairing students forget

RhoD Ig and postpartum live vaccines are notin conflict. A Rho(D)-negative mother without documented rubella/varicella immunity can receive her RhoD Ig andher MMR/varicella catch-up dose at the same postpartum visit, without regard to spacing between them.

Practice Reality: Oregon Pharmacist Scope

Worth knowing

Boards test the national ACIP framework, but day-to-day practice runs through state law. In Oregon, pharmacists prescribe and administer vaccines under statewide PHPFAC protocols(separate protocols exist for adults 18+, ages 7–17, and managing adverse reactions). Outside of influenza, an Oregon-licensed pharmacist may only prescribe and administer vaccines to patients age 7 and older(ORS 689.645), a scope limit that has nothing to do with vaccine science and everything to do with state statute.

The gap between ACIP guidance and real-world protocol updates isn't hypothetical either: in August 2025, FDA narrowed approval of updated COVID-19 vaccines to adults 65 and older and patients with underlying conditions, before ACIP had issued matching recommendations and while CDC was simultaneously shifting healthy children and pregnant patients toward shared clinical decision-making. Because state pharmacy protocols are typically built around ACIP recommendations, that lag created real access friction, hesitant pharmacies, prescription or attestation requirements, and confused patients, right in the middle of respiratory virus season. It's a useful reminder that "check the current ACIP schedule" isn't just an exam instruction, it's an operational habit.

Monitoring

ParameterWhenWatching for
Injection siteImmediately through 72 hoursPain, erythema, induration; expect ~80% injection-site pain with RZV, mild-moderate with diphtheria/tetanus toxoid
Systemic reaction0–72 hours after any pertussis-containing doseModerate fever (3–5%); rarely high fever, febrile seizure, persistent crying, or hypotonic-hyporesponsive episode
Acute hypersensitivity0–30 minutes post-injectionAnaphylaxis; observe per site protocol and report through VAERS
Pregnancy statusBefore any live vaccine, every visitConfirm not pregnant; counsel on avoiding pregnancy for 4 weeks after a rubella-containing dose
Immunosuppression timelineBefore any live vaccineConfirms the eligibility window: ≥3 months off chemo for leukemia, ≥1 month off high-dose/prolonged steroids
Adverse eventsAny suspected reactionReport through VAERS (Vaccine Adverse Event Reporting System), the federally maintained surveillance system

Patient Counseling

  • Tdap every pregnancy:"We give this in every pregnancy, not just your first, because the antibodies you make cross the placenta and protect your baby until they're old enough for their own first dose."
  • Live vaccine + pregnancy planning:"Since this is a live vaccine, we need you to avoid becoming pregnant for about 4 weeks afterward."
  • Wound visit needing both Td and TIg:"It's been more than 10 years since your last tetanus shot, and this wound is dirty enough that we're giving you both the booster and an antibody shot today, the booster builds your own protection, the antibody shot covers you immediately while that kicks in."
  • Zoster dose 1 and 2:"You'll likely get a sore arm for a day or two after each dose, sometimes redness or swelling. That's your immune system responding, it's expected, and it's actually a sign the vaccine is doing its job. Please still come back for dose two."
  • Immunosuppressed patient asking about a routine live vaccine:"We need to hold off on that until you've been off the high-dose steroid for a month" or "until you've been off chemotherapy for at least three months," so they understand it's a timing issue, not a permanent no.
  • HPV dosing surprise:"Because you're starting this before your 15th birthday, you only need two doses six months apart instead of three, your immune system responds strongly enough at this age that the extra dose isn't needed."
  • Postpartum RhoD Ig plus vaccines:"The Rho antibody shot you're getting today doesn't interfere with your MMR or chickenpox vaccine, it's safe to get all of them at this visit."

High-Yield Recall Sheet

  • Live vs. inactivated is the single factthat decides pregnancy and immunocompromise eligibility for any vaccine in this chapter.
  • Only one combination needs spacing:two different live vaccines given on different days need ≥4 weeks apart. Inactivated+inactivated, inactivated+live, or live+live same day all need zero spacing.
  • RZV (zoster) is not live, it's recombinant/adjuvanted, unlike MMR and varicella.
  • RZV:2 doses at 0 and 2–6 months, age ≥50, 91% effective against zoster.
  • Severely immunocompromised = no live vaccines, full stop, with two named exceptions below.
  • Exception 1:HIV patients still get MMR despite suboptimal response, because measles complication risk in HIV outweighs vaccine risk.
  • Exception 2:leukemia patients off chemotherapy ≥3 months may get live virus vaccines.
  • High-dose or >2-week corticosteroid course:wait ≥1 month after stopping before any live vaccine.
  • Measles vaccine indicated in anyone born after 1956without documented immunity.
  • D vs. d:pediatric-strength diphtheria toxoid (D) only through age 6; adults get lower-antigen d as Td/Tdap.
  • Adult Td series:one dose should be Tdap; boosters every 10 years; Tdap repeats every pregnancy regardless of prior doses.
  • Tetanus wound table:TIg is only for unknown/<3 prior doses AND a dirty/major wound. Fully immunized patients (≥3 doses) never need TIg.
  • TIg dosing gap:250–500 units IM for prophylaxis vs. 3,000–6,000 units IM for treating active tetanus, roughly a 10x difference.
  • HPV dose count depends on age at series start:2 doses if 9–14 years (6 months apart), 3 doses if ≥15 (0, 1–2, 6 months).
  • PCV and PPSV23 are sequenced, not interchangeable:immunocompromised adults get PCV20 or PCV15, then PPSV23 eight weeks later.
  • MenACWY (Menactra/Menveo) is routineat 11–12 plus a 16-year booster; MenB (Trumenba/Bexsero) is high-risk only, not routine.
  • Hib, MMR, varicella, and pneumococcal conjugateall share the general 12–15 month toddler dose plus 4–6 year booster rhythm.
  • RhoD Ig within 72 hours of deliverydrops active anti-Rho(D) antibody formation from 1% to 0.2%, and doesn't conflict with same-visit live vaccines.
  • Oregon pharmacistsmay only vaccinate patients ≥7 years old for non-influenza vaccines under state protocol, a state-law limit, not a national ACIP rule.