Norovirus vs Rotavirus vs Food Poisoning
Every comparison you will find online does two of these at a time — norovirus against "food poisoning", or norovirus against rotavirus — and the two-way version hides the fact that decides most cases: most food poisoning is norovirus. This page puts all three in one table, on the five things that actually separate them, and ends each row with the only question that matters to someone who is currently ill: what does the answer change?
The short version
Norovirus: 12–48 hours after exposure, vomiting first, over in 1–3 days, any age, every winter, no vaccine, no antibiotic — and 58% of all US food poisoning from a known cause. Rotavirus: under 48 hours to onset, diarrhea for 3–7 days, infants and children under five, winter–spring, a vaccine that has cut it by more than half. "Food poisoning" that is not norovirus: either a toxin that hits within hours and is gone in a day (Staph, B. cereus, C. perfringens), or a bacterial infection that takes days to start and a week to clear (Salmonella, Campylobacter, E. coli O157). The management changes are few and specific: fluids for everyone; a vaccine for one; antibiotics for almost none and possibly harmful for one; a stool test and a longer exclusion if there is blood.
The three-way table
"Food poisoning" is not one illness, so its column is split where the split matters: the toxin illnesses, where the bacteria made their poison in the food before you ate it, and the infections, where live bacteria colonise you. Timing is from FDA's Bad Bug Book; norovirus figures are CDC's as verified on our symptoms page; rotavirus figures are from CDC surveillance papers and the vaccine labels.
| Norovirus | Rotavirus | Food poisoning — toxin type S. aureus, B. cereus, C. perfringens | Food poisoning — bacterial infection Salmonella, Campylobacter, STEC/E. coli O157, Shigella | |
|---|---|---|---|---|
| Onset after exposure | 12–48 hours; median 33–36 hours in outbreaks (FDA), as early as 12 | Under 48 hours (FDA) | 30 minutes to 16 hours. S. aureus 1–7 h; B. cereus emetic 0.5–6 h, diarrheal 6–15 h; C. perfringens ~16 h | Hours to days. Salmonella 6–72 h; Shigella 8–50 h; Campylobacter 2–5 days; STEC O157 3–4 days (range 1–9) |
| First symptom, character | Sudden, often projectile vomiting; watery, non-bloody diarrhea; cramps; low fever in some | Vomiting and fever, then watery diarrhea that can dehydrate a small child quickly; non-bloody | Vomiting (Staph, emetic B. cereus) or watery diarrhea with cramps (C. perfringens, diarrheal B. cereus); fever unusual | Diarrhea with fever and cramps; bloody stool is the flag for Campylobacter, Shigella and STEC (STEC: bloody, fever low or absent) |
| How long it lasts | 1–3 days (CDC); FDA: 12–60 h, mean 24–48 h; longer in the elderly and immunocompromised. Shedding for 2 weeks or more after | 3–7 days of diarrhea (FDA) | Hours to a day. Staph "a few hours to one day"; C. perfringens 12–24 h (1–2 weeks in the elderly or infants) | A week or so. Salmonella 4–7 days; Shigella 5–7; Campylobacter 2–10; STEC 2–9 (average 8) |
| Who gets it | Everyone, repeatedly. 19–21 million US illnesses a year; deaths mostly over 65, emergency visits mostly young children; reinfection throughout life (why) | Infants and children under 5. Pre-vaccine: 55,000–70,000 US child hospitalizations a year (Aliabadi 2015); nearly every child infected by age 5; adults reinfected but mildly (Crawford 2017) | Anyone who ate the dish — the classic shared-meal cluster with everyone ill within the same few hours | Anyone; severe disease concentrates in the very young, the old and the immunocompromised. STEC's hemolytic uremic syndrome (3–7% of hemorrhagic colitis) is chiefly a childhood complication |
| Season | Winter — 75% of long-term-care outbreaks fall in December–March (Calderwood 2022); the GII.4 years are the bad years (strain table) | Winter–spring, sweeping west to east: starting in the West in December–January and ending in the Northeast in April–May before vaccination; now a biennial pattern of low and moderate years (Aliabadi 2015) | Year-round; tied to catering, buffets and food held at the wrong temperature, so summer picnics and holiday meals | Summer peaks for Salmonella, Campylobacter and STEC in US surveillance; year-round otherwise |
| Share of US "food poisoning" | 58% of foodborne illnesses from 31 known pathogens (Scallan 2011); 48% of foodborne outbreaks with a single known cause (Hall 2014); 59% of all enteric outbreaks reported to CDC 2009–2019 (Wikswo 2022) | Rarely foodborne — spread person to person and in childcare; a minor share of foodborne illness | C. perfringens 10% of foodborne illnesses; S. aureus and B. cereus smaller (Scallan 2011) | Nontyphoidal Salmonella 11% of illnesses but 35% of hospitalizations and 28% of deaths; Campylobacter 9% (Scallan 2011) |
| What the diagnosis changes | Fluids; no antibiotic; no vaccine. Food workers excluded until 48 hours after symptoms end (Food Code §2-201); bleach, not alcohol, for surfaces; 48-hour rule for schools and daycare in most states | Fluids; no antibiotic; a vaccine exists. RotaTeq (3 oral doses, 6–32 weeks) or Rotarix (2 doses, 6–24 weeks) — the one column where the illness is preventable by a shot the infant should already have had | Fluids; nothing else. The toxin is already in you; antibiotics have no target. Diagnosis is by the clock and the shared meal. Report a cluster so the kitchen is inspected | Stool test if there is blood or fever, and before any antibiotic. Uncomplicated Salmonella and Campylobacter are self-limiting; Shigella sometimes treated; STEC: FDA notes antibiotics "in some instances seem to increase the patient's risk of HUS" — so no antibiotic and watch for reduced urine. Food-worker exclusion continues until cleared by the health authority |
Why the two-way comparisons mislead
Set norovirus against "food poisoning" and the comparison assumes they are different things. In US surveillance they mostly are not: of the 9.4 million foodborne illnesses a year that CDC attributes to a known pathogen, 5.5 million — 58% — are norovirus (Scallan et al. 2011), and it caused 48% of foodborne outbreaks with a single known cause in 2009–2012, 64% of them in restaurants and 70% traced to an infected food worker (Hall et al. 2014). A person who ate out on Saturday and was vomiting on Monday morning has, on the numbers, most probably had norovirus — from the hands of whoever plated the salad, not from anything that grew in it.
What the two-way comparison gets right is the part of "food poisoning" that is genuinely not norovirus, and the table above splits it because its two halves behave in opposite ways. The toxin illnesses are fast and short: Staphylococcus aureus enterotoxin acts in 1 to 7 hours and is over within a day; Bacillus cereus emetic toxin in as little as 30 minutes. If everyone at the party was ill by bedtime, it was a toxin, not a virus — norovirus is not that quick, and rotavirus is not that adult. The bacterial infections are slow and long: Campylobacter takes two to five days to start and up to ten to clear; E. coli O157 three to four days to start and, on average, eight to run its course. Bloody diarrhea, fever and a week of illness point away from both viruses.
Set norovirus against rotavirus and the comparison is fair but incomplete, because it leaves out the one that matters to adults. The two viruses are distinguished by age and by policy. Rotavirus was, before 2006, the leading cause of severe dehydrating gastroenteritis in US children — 55,000 to 70,000 hospitalizations and 410,000 clinic visits a year — with a winter–spring season that began in the West in December and finished in the Northeast in April (Aliabadi et al. 2015). Vaccination cut laboratory detections by 57.8% to 89.9% in every post-vaccine year and broke the annual season into a biennial one. Globally, across 49 countries, rotavirus hospitalizations fell by a median 59% after vaccine introduction (Burnett et al. 2020). Norovirus has none of that: it infects every age, immunity lasts months and is strain-specific, and there is no licensed vaccine — which is why it is the virus this site exists for.
The management row, expanded
The last row of the table is the reason to tell the three apart at all. Symptom relief is the same for every column — fluids, rest, oral rehydration for the young and old — so the differences are the four things that are not the same.
- Antibiotics. Useless against both viruses and against the toxin illnesses. For the bacterial infections, FDA's Bad Bug Book describes uncomplicated Salmonella and Campylobacter as self-limiting and names Shigella as the one where antibiotics are sometimes given. For Shiga toxin-producing E. coli it records that antibiotic therapy "has had mixed results and, in some instances, seems to increase the patient's risk of HUS", the kidney complication that reaches 3–7% of hemorrhagic colitis cases and kills 3–5% of those. That is the single most important line in the table: bloody diarrhea is a reason to be tested, not a reason to be treated blind.
- Vaccination. Only rotavirus has one. Both US products are oral and given in infancy — RotaTeq from 6 to 32 weeks, Rotarix from 6 to 24 weeks (FDA labels) — so the practical implication is for parents of infants, not for anyone who is currently ill. A vaccinated child can still get norovirus; a norovirus vaccine remains in trials (the immunity problem behind that).
- Exclusion from work and school. The FDA Food Code excludes any food employee with vomiting or diarrhea until 24 hours symptom-free, extends that to 48 hours for a diagnosed norovirus infection, and for Shigella, STEC, Salmonella Typhi and hepatitis A keeps the worker out until the regulatory authority clears them (§2-201, as set out on our food-handler rules page). Schools and daycares run on similar symptom-based clocks, state by state (our table). The diagnosis therefore changes the calendar: a toxin illness is a day off; norovirus is two symptom-free days; a positive STEC or Shigella test can be weeks.
- Cleanup. Norovirus is non-enveloped and survives alcohol; CDC's guidance is bleach on surfaces and soap-and-water on hands, which our prevention page sets out. Rotavirus is also non-enveloped. For a toxin illness there is nothing to disinfect — the problem was the food, not the person.
A decision rule that fits on a card
Ill within hours of a shared meal, better by tomorrow: a food toxin; nothing to treat, report the meal. Ill a day or two later, vomiting first, better in two days, others in the house following: norovirus; fluids, bleach, 48 hours before returning to food work. An infant or toddler with days of watery diarrhea in winter or spring: think rotavirus; fluids and a check that the vaccine series was given. Fever, cramps, a week of illness, or any blood: a bacterial infection; get a stool test, and do not start an antibiotic until the result rules out Shiga toxin-producing E. coli.
Frequently asked questions
How can I tell norovirus from food poisoning?
By the clock, mostly. Norovirus starts 12–48 hours after exposure and lasts 1–3 days; the toxin food poisonings start within hours and are gone in a day; the bacterial infections take days to start and a week to clear, often with blood or fever. But 58% of US foodborne illness from a known cause is norovirus (Scallan 2011), so the two are usually the same event.
What is the difference between norovirus and rotavirus?
Age, duration and a vaccine. Rotavirus is an under-five disease with 3–7 days of diarrhea and a winter–spring season, cut by 58–90% a year since the 2006 vaccines (Aliabadi 2015). Norovirus infects all ages for 1–3 days, every winter, with no vaccine and short, strain-specific immunity.
Do you need antibiotics?
Not for either virus or for a toxin illness, and not usually for Salmonella or Campylobacter. For Shiga toxin-producing E. coli, FDA notes antibiotics may increase the risk of hemolytic uremic syndrome — so bloody diarrhea means a stool test first. Shigella is sometimes treated.
When can a food worker or a child go back?
Food Code §2-201: 24 hours symptom-free for undiagnosed vomiting or diarrhea, 48 hours for diagnosed norovirus, and until the health authority clears the worker for Shigella, STEC, Salmonella Typhi and hepatitis A. Schools and daycares follow similar symptom clocks — see our exclusion page.
Which one should I worry about?
Blood in the stool (bacterial, needs testing) and dehydration (any of them, dangerous at the extremes of age). An infant under three months with vomiting or diarrhea, or anyone who cannot keep fluids down for a day, needs care whatever the cause.
This page compares published timing, epidemiology and management rules; it is not medical advice and cannot diagnose anyone. Bloody diarrhea, high fever, signs of dehydration, or any vomiting or diarrhea in an infant under three months need a clinician — see the "when to seek care" list on our symptoms page.
Sources & References
- U.S. Food and Drug Administration. Bad Bug Book: Foodborne Pathogenic Microorganisms and Natural Toxins, 2nd edition (2012) — onset, duration, symptoms and complications for Salmonella, Campylobacter jejuni, enterohemorrhagic E. coli (HUS 3–7% of hemorrhagic colitis; HUS mortality 3–5%; antibiotic caution), Shigella, Clostridium perfringens, Staphylococcus aureus, Bacillus cereus, noroviruses and rotavirus. fda.gov (PDF)
- Centers for Disease Control and Prevention. Norovirus symptoms, onset (12–48 hours), duration (1–3 days) and shedding, as cited with dates on our symptoms page; foodborne-share statements on our food safety page. cdc.gov/norovirus
- Scallan E, Hoekstra RM, Angulo FJ, et al. Foodborne illness acquired in the United States — major pathogens. Emerg Infect Dis 2011;17(1):7–15 — 9.4 million illnesses from 31 pathogens; norovirus 58%, nontyphoidal Salmonella 11%, C. perfringens 10%, Campylobacter 9%; hospitalization and death shares. doi:10.3201/eid1701.p11101
- Hall AJ, Wikswo ME, Pringle K, Gould LH, Parashar UD. Vital signs: foodborne norovirus outbreaks — United States, 2009–2012. MMWR 2014;63(22):491–5 — 48% of single-cause foodborne outbreaks; restaurants 64%; food workers 70%. PubMed 24898166
- Wikswo ME, Roberts V, Marsh Z, et al. Enteric illness outbreaks reported through the National Outbreak Reporting System — United States, 2009–2019. Clin Infect Dis 2022;74(11):1906–13 — norovirus 59% of 38,395 outbreaks; hospitalization 2% (norovirus) vs 20.9% (Salmonella) and 22.8% (E. coli). doi:10.1093/cid/ciab771
- Calderwood LE, Wikswo ME, Mattison CP, et al. Norovirus outbreaks in long-term care facilities in the United States, 2009–2018. Clin Infect Dis 2022;74(1):113–9 — 75% of outbreaks in December–March. doi:10.1093/cid/ciab808
- Aliabadi N, Tate JE, Haynes AK, Parashar UD. Sustained decrease in laboratory detection of rotavirus after implementation of routine vaccination — United States, 2000–2014. MMWR 2015;64(13):337–42 — 55,000–70,000 hospitalizations and 410,000 clinic visits a year pre-vaccine; West-to-Northeast December–May seasonality; 57.8–89.9% declines; biennial pattern. PubMed 25856253
- Burnett E, Parashar UD, Tate JE. Global impact of rotavirus vaccination on diarrhea hospitalizations and deaths among children <5 years old: 2006–2019. J Infect Dis 2020;222(10):1731–9 — median 59% reduction in rotavirus hospitalizations across 49 countries. doi:10.1093/infdis/jiaa081
- Crawford SE, Ramani S, Tate JE, et al. Rotavirus infection. Nat Rev Dis Primers 2017;3:17083 — leading cause of severe dehydrating gastroenteritis in children under 5; reinfection throughout life with reduced severity; management centred on dehydration. doi:10.1038/nrdp.2017.83
- U.S. Food and Drug Administration. RotaTeq (rotavirus vaccine, live, oral, pentavalent) — approved for infants 6 to 32 weeks of age. fda.gov
- U.S. Food and Drug Administration. Rotarix (rotavirus vaccine, live, oral) — approved for infants 6 to 24 weeks of age. fda.gov
- U.S. Food and Drug Administration. Food Code 2022, §2-201 — exclusion and restriction of ill food employees, including the 24-hour and 48-hour (norovirus) rules and the regulatory-authority clearance for Shigella, STEC, Salmonella Typhi and hepatitis A, as worked through on our food-handler rules page. fda.gov
Norovirus Symptoms
The hour-by-hour timeline, the challenge-study data, and when to seek care.
Food Safety
How food gets contaminated, which foods, and what cooking does and does not do.
Food-Handler Rules
The Food Code exclusion clocks, pathogen by pathogen, with 80 practice questions.
Immunity & Reinfection
Why norovirus has no vaccine yet and rotavirus does.
