Vitamin K, Eye Ointment, and the Hepatitis B Vaccine: Your Newborn’s First Medicines Explained

Key takeaways: The vitamin K shot prevents a rare but potentially fatal bleeding disorder. Erythromycin eye ointment prevents a serious eye infection that can cause blindness. The hepatitis B vaccine protects against a lifelong liver infection. All three have long safety records and are recommended by the AAP.

In the first hours after birth, your care team will offer three routine treatments. Parents often have questions about them, and some see conflicting information online. Here’s what each one does, why it’s recommended, and what the evidence says.

1. The Vitamin K Shot

Why Babies Need It

Vitamin K helps blood clot. Newborns are born with very low levels because only small amounts cross the placenta, their guts don’t yet have the bacteria that make vitamin K, and breast milk is naturally low in it. Without enough vitamin K, babies are at risk for vitamin K deficiency bleeding (VKDB), sometimes called hemorrhagic disease of the newborn.

What VKDB Looks Like

VKDB can happen:

• Early (first 24 hours), most often in babies whose birthing parent took certain medications.
• Classic (days 2 to 7), with bleeding from the umbilical cord, nose, gut, or circumcision site.
• Late (2 weeks to 6 months, most often at 3 to 8 weeks), the most dangerous form. About half of babies with late VKDB bleed into the brain, often with no warning signs. Many survivors have lasting brain damage, and some die.

How Well It Works

Without vitamin K, late VKDB affects roughly 4 to 7 of every 100,000 babies. A single vitamin K injection at birth nearly eliminates that risk. The CDC reports that babies who don’t get the shot are 81 times more likely to develop late VKDB than those who do. In 2013, after several infants in Tennessee developed serious bleeding, health investigators found the parents had declined the shot.

Common Questions

• Is it safe? Yes. The AAP has recommended a single intramuscular dose of vitamin K at birth since 1961. An early study raised concerns about a link to childhood cancer, but larger, later studies didn’t confirm it.
• What about oral vitamin K? Oral doses are less effective at preventing late VKDB, require multiple doses over weeks, and there’s no FDA-approved oral form in the United States. The injection is the recommended method.
• Can it be given during skin-to-skin? Often, yes. Breastfeeding or skin-to-skin during the shot can reduce pain.

2. Erythromycin Eye Ointment

Why Babies Get It

Bacteria such as Neisseria gonorrhoeae can be passed to a baby’s eyes during birth and cause ophthalmia neonatorum, a serious eye infection that can damage the cornea and cause blindness within days. Many people with gonorrhea don’t have symptoms, and infections can be acquired after prenatal testing.

The Evidence

The U.S. Preventive Services Task Force reaffirmed in 2019 its strong (Grade A) recommendation for preventive eye ointment for all newborns. Erythromycin is the only antibiotic eye ointment currently recommended for this use in the U.S. Many states require it by law.

Common Questions

• Does it hurt? No. It may blur your baby’s vision briefly. It can be given after the first hour of skin-to-skin and feeding.
• What if I had a cesarean or tested negative? Ask your provider. The recommendation is universal because infections can be missed or acquired late, but policies and state laws vary.

3. The Hepatitis B Vaccine

Why Babies Get It

Hepatitis B is a virus that attacks the liver. About 90 percent of infants infected at birth develop lifelong (chronic) infection, which can lead to liver failure, liver cancer, and early death. Infection can come from a birthing parent who carries the virus, sometimes without knowing it, or from close contact with others in the household.

The Evidence

Since universal hepatitis B vaccination began in 1991, infections in U.S. children have dropped by about 99 percent. The full vaccine series protects more than 98 percent of healthy infants.

Current Recommendations

The AAP recommends the first dose within 24 hours of birth for all medically stable babies weighing at least 2,000 grams (about 4.4 pounds), followed by doses between 1 and 2 months and between 6 and 18 months. Babies born to parents who test positive for hepatitis B, or whose status is unknown, need the vaccine (and sometimes hepatitis B immune globulin) within 12 hours of birth.

Federal vaccine recommendations, including those for the birth dose, changed in late 2025 and early 2026, and parts of those changes are currently under court review. As of October 2026, the AAP’s recommendation for a universal birth dose has not changed. Ask your baby’s doctor which schedule they follow and talk through any questions you have.

Common Questions

• Why so early? The birth dose provides immediate protection during the period when infection is most likely to become lifelong, and it’s a safety net in case prenatal test results are wrong, missed, or out of date.
• Is it safe? The hepatitis B vaccine has been used in infants for more than three decades and has an excellent safety record. Mild soreness at the injection site is the most common side effect.

Talking With Your Care Team

You have the right to ask questions about any treatment your baby receives. Good questions include:

• What does this prevent, and how common is that condition?
• What are the side effects?
• Can it be given during skin-to-skin or after the first feed?
• What happens if we decline, and what signs should we watch for?

If you’re unsure, ask to talk with your baby’s pediatrician before you go home.

The Bottom Line

The vitamin K shot, eye ointment, and hepatitis B vaccine each prevent rare but devastating conditions, and each has decades of safety data. They’re quick, low-risk ways to protect your baby in their first days.

My book From First Breath to First Birthday explains every routine newborn procedure and screening in plain language.

Related Articles

• Your Baby’s Vaccine Schedule in 2026: What Changed and What Didn’t
• Your Newborn’s First 24 Hours: What Happens in the Hospital, Hour by Hour
• RSV in Babies: Prevention, Symptoms, and When to Go to the ER

Sources

1. American Academy of Pediatrics Committee on Fetus and Newborn. Controversies concerning vitamin K and the newborn. Pediatrics. 2003;112(1 Pt 1):191-192.
2. Centers for Disease Control and Prevention. Vitamin K deficiency bleeding: facts. https://www.cdc.gov/ncbddd/vitamink
3. Schulte R, Jordan LC, Morad A, Naftel RP, Wellons JC 3rd, Sidonio R. Rise in late onset vitamin K deficiency bleeding in young infants because of omission or refusal of prophylaxis at birth. Pediatr Neurol. 2014;50(6):564-568.
4. Warren MD, Miller AM, Traylor J, Bauer A, Patrick SW. Notes from the field: late vitamin K deficiency bleeding in infants whose parents declined vitamin K prophylaxis—Tennessee, 2013. MMWR Morb Mortal Wkly Rep. 2013;62(45):901-902.
5. Sankar MJ, Chandrasekaran A, Kumar P, Thukral A, Agarwal R, Paul VK. Vitamin K prophylaxis for prevention of vitamin K deficiency bleeding: a systematic review. J Perinatol. 2016;36(Suppl 1):S29-S35.
6. US Preventive Services Task Force. Ocular prophylaxis for gonococcal ophthalmia neonatorum: US Preventive Services Task Force reaffirmation recommendation statement. JAMA. 2019;321(4):394-398.
7. American Academy of Pediatrics. Hepatitis B. https://www.aap.org/en/patient-care/hepatitis-b/
8. American Academy of Pediatrics. AAP Immunization FAQs: Hepatitis B. Accessed October 2026. https://www.aap.org/en/patient-care/immunizations/aap-immunization-faq/
9. Congressional Research Service. Changes to CDC Vaccine Recommendations in 2025 and 2026. IN12684. https://www.congress.gov/crs-product/IN12684

This article is for general education and is not a substitute for individualized medical advice. Always talk with your baby’s health care provider or your own provider about your specific situation. If you think your baby or you may have a medical emergency, call 911.