If flu season comes while you're pregnant, get one inactivated flu vaccine shot, which can be given at any stage of pregnancy; don't use the nasal spray

Cost

Self-paid, a few dozen to a little over 100 CNY per shot. One trip to the community vaccination clinic. The hard part is choosing a vaccine whose package insert does not list pregnant women as a contraindication.

What you get

The World Health Organization's 2022 position paper pooled the existing studies. A pregnant woman with influenza has about 7 times the risk of hospitalization of a woman who is not pregnant (OR 6.8, 95% CI 6–7.7, the plausible range). In a trial in Bangladesh, 340 pregnant women were randomly divided into two groups. One group received an inactivated influenza vaccine and the other a pneumococcal vaccine as the control, and they were followed until the babies were 24 weeks old. Among babies of the influenza-vaccine group, there were 6 confirmed flu cases versus 16 in the control group, a vaccine efficacy of 63% (95% CI 5–85). The mothers' own fever plus respiratory illness was 36% lower (95% CI 4–57). Two trials in South Africa used a placebo, and neither the doctors nor the pregnant women knew which shot was given. Among women without HIV, confirmed flu fell from 3.6% to 1.8%, an efficacy of 50.4% (95% CI 14.5–71.2). In their babies it fell from 3.6% to 1.9%, an efficacy of 48.8% (95% CI 11.6–70.4). Pooling 4 trials and 3 observational studies, confirmed flu in babies within 6 months was about 48% lower (95% CI 33–59). 4 observational studies looked at babies hospitalized for confirmed flu and found it about 72% lower (95% CI 39–87). Another pooled analysis combined only two trials and found confirmed flu 34% lower (95% CI 15–50). But there was no difference in the babies' “influenza-like illness,” which means illness that looks like flu by symptoms alone, with no lab test. For the pregnant women's own hospitalizations, medical records from four countries for 2010 to 2016 were used. For hospitalization for confirmed flu, those who had been vaccinated were about 40% lower (95% CI 12–59). On safety, one pooled analysis included 40 studies. Among the vaccinated, stillbirth aOR 0.84 (0.65–1.08) and congenital malformation 1.03 (0.99–1.07). Both differences were within the margin of error. Preterm birth was 0.87 (0.78–0.96), about 13% lower. In the U.S., three flu seasons from 2012 to 2015 were examined. Vaccination within 28 days before a miscarriage had aOR 0.9 (0.6–1.5), no association. The Chinese Center for Disease Control and Prevention's (中国疾控中心) guidelines for the 2026—2027 season list pregnant women as a priority group for vaccination. It says vaccination at any stage of pregnancy protects babies under 6 months old, and works better in late pregnancy. Live attenuated vaccines are prohibited for pregnant women.

Notes

A dispute. A 2017 U.S. study found more miscarriages among people who had received a flu vaccine within the 28 days before the miscarriage (aOR 2.0, 1.1–3.6). The excess appeared only among people who had also received a vaccine containing the A(H1N1) component the previous season. The authors themselves say this cannot prove causation. The same group was checked over the three flu seasons that followed and the association was not seen again, so countries still say it can be given at any stage of pregnancy. Some flu vaccine package inserts in China still list pregnant women as a contraindication. The guidelines advise choosing one whose insert does not list pregnant women as a contraindication, and telling the vaccinating doctor you are pregnant before the shot. Get only the injected inactivated vaccine. The one sprayed into the nose is a live attenuated vaccine; in China it is given only to ages 3 to 17, and pregnant women are prohibited from receiving it. It is best to finish before the local flu season begins, generally September to October. If you miss that, you can still catch up at any point during the whole flu season. A baby under 6 months old cannot get a flu vaccine, so the shot in pregnancy is the main protection for the baby in the first months. Family members who live with you and people who care for the baby are also priority groups; for the account of an adult getting the flu vaccine for themselves, see §1.20 (get a flu vaccine). The benefits column has no mortality figures; the size of the benefit was rated by confirmed flu and hospitalization, with the reasoning in the verification record. The benefit falls on you and your baby.

Evidence grade

A : Specific numbers from meta-analyses, large cohorts or randomized trials; for law and policy, the statute or official text.

Sources

1. World Health Organization (2022). Vaccines against influenza: WHO position paper – May 2022. Weekly Epidemiological Record, 97(19), 185-208. https://iris.who.int/server/api/core/bitstreams/420b8e49-9f16-461d-a5d8-263069778432/content
2. Zaman K, Roy E, Arifeen SE, et al. (2008). Effectiveness of maternal influenza immunization in mothers and infants. New England Journal of Medicine, 359(15), 1555-1564. https://doi.org/10.1056/NEJMoa0708630
3. Madhi SA, Cutland CL, Kuwanda L, et al. (2014). Influenza vaccination of pregnant women and protection of their infants. New England Journal of Medicine, 371(10), 918-931. https://doi.org/10.1056/NEJMoa1401480
4. Nunes MC, Madhi SA (2018). Influenza vaccination during pregnancy for prevention of influenza confirmed illness in the infants: A systematic review and meta-analysis. Human Vaccines & Immunotherapeutics, 14(3), 758-766. https://doi.org/10.1080/21645515.2017.1345385
5. Jarvis JR, Dorey RB, Warricker FDM, Alwan NA, Jones CE (2020). The effectiveness of influenza vaccination in pregnancy in relation to child health outcomes: Systematic review and meta-analysis. Vaccine, 38(7), 1601-1613. https://doi.org/10.1016/j.vaccine.2019.12.056
6. Thompson MG, Kwong JC, Regan AK, et al. (2019). Influenza Vaccine Effectiveness in Preventing Influenza-associated Hospitalizations During Pregnancy: A Multi-country Retrospective Test Negative Design Study, 2010-2016. Clinical Infectious Diseases, 68(9), 1444-1453. https://doi.org/10.1093/cid/ciy737
7. Giles ML, Krishnaswamy S, Macartney K, Cheng A (2019). The safety of inactivated influenza vaccines in pregnancy for birth outcomes: a systematic review. Human Vaccines & Immunotherapeutics, 15(3), 687-699. https://doi.org/10.1080/21645515.2018.1540807
8. Donahue JG, Kieke BA, King JP, et al. (2019). Inactivated influenza vaccine and spontaneous abortion in the Vaccine Safety Datalink in 2012-13, 2013-14, and 2014-15. Vaccine, 37(44), 6673-6681. https://doi.org/10.1016/j.vaccine.2019.09.035
9. Donahue JG, Kieke BA, King JP, et al. (2017). Association of spontaneous abortion with receipt of inactivated influenza vaccine containing H1N1pdm09 in 2010-11 and 2011-12. Vaccine, 35(40), 5314-5322. https://doi.org/10.1016/j.vaccine.2017.06.069（备注里的反方研究）
10. 中国疾病预防控制中心 (2026). 中国流感疫苗预防接种技术指南（2026—2027）. https://www.chinacdc.cn/jkyj/mygh02/jswj2026/202609/t20260902_1839739.html

Translated from the Chinese original. Original book, section 27, tip 18. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer