Protects against the hepatitis B virus — offered through Ontario's Grade 7 school program
Protects against the hepatitis B virus, which affects the liver.
Hepatitis B is a virus that infects the liver. It can cause short-term illness, but the bigger concern is long-term (chronic) infection, which can develop quietly over years.
| What hepatitis B can cause | What people might notice | How it spreads | Why it can be serious | How vaccination helps |
|---|---|---|---|---|
| Acute (short-term) infection | Sometimes no symptoms; sometimes tiredness, nausea, tummy pain, or yellowing of the skin and eyes (jaundice). | Through contact with infected blood or certain body fluids — for example, from mother to baby at birth, sharing personal items that may have blood on them, or other blood/fluid contact. | Most healthy older children and adults recover, but some develop chronic infection — and the younger a person is when infected, the higher the chance it becomes chronic. | The vaccine prompts the immune system to recognize and fight the virus, preventing infection. |
| Chronic (long-term) infection | Often silent for years, with no obvious symptoms, while quietly affecting the liver. | A chronic carrier can pass the virus to others through blood/fluid contact. | Over time, chronic hepatitis B can lead to serious liver disease, including scarring (cirrhosis) and liver cancer. | By preventing infection in the first place, the vaccine prevents the chronic infection that leads to these long-term harms. |
Why Grade 7? Hepatitis B is offered in Grade 7 to build protection during adolescence, before most exposure risks arise. Offering it through school clinics makes it easy to reach all students. For this age group, a 2-dose schedule provides good protection.
Why two doses? When given to adolescents in this age range, two doses of the vaccine provide protection. The spacing depends on the product used — Recombivax HB doses are given about 4 months apart (0 and 4 months), and Engerix-B doses about 6 months apart (0 and 6 months). Those who start older, or who have certain medical conditions, may need a different (often 3-dose) schedule.
What if a dose is late? If the second dose is delayed, the series does not need to restart — the next dose can be given when possible. A healthcare provider or public health unit can confirm timing. See the Catch-Up & Missing Records page.
Can it be given with other vaccines? Yes. In Grade 7, hepatitis B is offered alongside the meningococcal ACYW and HPV vaccines through the school program. These may be given at the same visit, at different injection sites.
This distinction is a common source of confusion, because hepatitis B is offered at school alongside the meningococcal ACYW vaccine — and meningococcal disease is ISPA-required. It's easy to assume everything offered in the school clinic carries the same requirement, but it doesn't. Hepatitis B (and HPV) are publicly funded, school-based, and recommended, but participation is a choice rather than a school-attendance requirement.
What "school-based" means here: Public health nurses typically visit schools to offer these vaccines, which makes them convenient and accessible. Parents and caregivers are asked to provide consent. If your child misses the school clinic, the vaccine remains free through your local public health unit (through Grade 12), and sometimes through other providers.
Reporting: When the vaccine is given through a school-based clinic run by public health, the public health unit usually records it directly. If your child receives hepatitis B vaccine elsewhere, you may need to report it to your local public health unit yourself.
Two hepatitis B products are used in Ontario's program: Recombivax HB® (Merck) and Engerix®-B (GSK). Both are "recombinant" vaccines — the active ingredient is a protein from the surface of the virus, made using yeast, with no live or whole virus. Neither can cause hepatitis B. The information below is based on their Health Canada product monographs.
| Ingredient / Component | Category | Why it's there | Plain-English explanation |
|---|---|---|---|
| Hepatitis B surface antigen (recombinant) | Active ingredient | Trains the immune system to recognize the hepatitis B virus. | A single protein from the surface of the virus, made in yeast cells through genetic engineering ("recombinant"). It's just the outer protein — there's no live virus and no viral genetic material, so it can't cause infection. |
| Aluminum (as an aluminum salt) | Adjuvant | Helps the immune system respond more strongly and produce longer-lasting protection. | An aluminum-based adjuvant, used in small amounts with a long record of safe use. Aluminum is also found in everyday foods and water. |
| Yeast protein (trace amounts) | Manufacturing process residual / potential allergen | The surface protein is grown using yeast, so trace amounts may remain. | Relevant for anyone with a known severe yeast allergy — discuss with a provider if it applies to your child. |
| Sodium chloride | Tonicity agent | Helps match the vaccine's salt concentration to the body's. | Ordinary salt, so the injection is gentler on the tissues. |
| Buffer agents (sodium borate in Recombivax; disodium phosphate in Engerix-B) | Buffers | Help keep the vaccine at a stable acidity (pH). | Small amounts of salts that keep the product stable. The specific buffer differs between the two products. |
| Formaldehyde (trace amounts, in Recombivax) | Manufacturing process residual | Used during manufacturing; trace amounts may remain. | Any remaining amount is very small — less than the body naturally produces during normal metabolism. |
| Water for injection | Base | The liquid base of the vaccine. | Sterile water making up most of the injection. |
Expected / common side effects
Timing and duration: These reactions usually appear within a day or so and typically resolve within 1–2 days.
Fainting: Fainting can happen after any vaccine in adolescents, and is more about the experience of being vaccinated than the vaccine itself. Because of this, the person giving the vaccine may ask your child to sit or stay nearby for about 15 minutes afterward. Let the clinic know if your child has fainted with needles before.
Home care: A cool compress can help with injection-site soreness. Acetaminophen or ibuprofen may be used as directed for discomfort or fever. People under 19 should not be given ASA (Aspirin) or salicylate-containing products.
Mild side effects can happen as the immune system responds. Many people have no side effects at all, and that does not mean the vaccine didn't work.
Rare but important
What clinics do to reduce risk: Clinics ask about allergy history before vaccination, are equipped with epinephrine and trained staff, and have your child sit during and after the injection to reduce the chance of injury from fainting.
Observation period: Staying seated and nearby for about 15 minutes after the vaccine is recommended, which addresses both rare severe allergic reactions and the more common possibility of fainting.
A note on safety monitoring: Hepatitis B vaccines have been used worldwide for decades and have a strong safety record. They continue to be monitored for safety.
Get urgent help now if your child has:
If any of these occur, go to the nearest emergency department or call 911. Otherwise, contact a healthcare provider and let them know what happened — this information also helps with vaccine safety monitoring.
Speak with a healthcare provider before this vaccine if:
These usually do NOT require delaying this vaccine:
Where to get it
Offered free through Grade 7 school clinics run by your local public health unit. Also available free through the public health unit (through Grade 12).
What to bring / do
Watch for the consent form sent home through school, and return it on time. Note any allergies or a history of fainting with needles.
If you missed the school clinic
Contact your local public health unit to arrange a free dose. Catch-up is funded through Grade 12.
If records are missing
Your public health unit usually records school-clinic doses directly. Contact them to confirm what's on file.
If vaccinated outside Ontario
Bring any records to a healthcare provider or public health unit so the series can be reviewed and continued if needed.
Contact public health
For consent questions, scheduling, or to report a dose given elsewhere, see the Resources page for your local public health unit.
This page is based on:
Please note: This is an independent website. It is not affiliated with, endorsed by, or operated by the Government of Ontario, the Ministry of Health, or any public health unit. The information here is for general education only and is not medical advice — always consult a licensed healthcare provider about your or your child's immunizations.